Metallic tellurium for p-type contacts of two-dimensional MoTe_2 field-effect transistors

Domain: physics
Published: 2026-01-13
Editorial outcome: accept

Abstract
Whilesignificantprogresshasbeenmadeinthefabricationofn-typecontacts
fortwo-dimensionalfield-effecttransistors(2DFETs),thedevelopmentof
high-performancep-typecounterpartsusingcompatibletechniquesremains
insufficienttorealizecompetitivecomplementarycircuits.Here,wedemon-
stratethegrowthofmetallic-phasetellurium(m-Te)onMoTe viaevaporation
2
asanefficientp-typecontact.TheatomicarrangementattheTe/MoTe
2
interfacestabilizesm-Teunderambientconditions,forminganatomically
sharpvanderWaalsgapwithoptimalbandalignmentandsuppressedmetal-
inducedgapstates.Combinedwithholedopingandtelluriumvacancies
compensation,theinterfaceenablesbarrier-freeholeinjection.BilayerMoTe
2
FETsemployingm-Tecontactsachieveacontactresistanceaslowas1.6kΩ
μm,anon-statecurrentupto124μAμm-1,andamaximumon/offratioof107,
whichareamongthebestvaluesobtainedforp-type2DFETs.Ourworkunveils
metallic-phasechalcogenasapromisingapproachforcontactoptimization.

Introduction
Theatomicallythinbodiesanddanglingbond-freesurfacesoftwo-
dimensional(2D)semiconductorsmakethempromisingcandidates
for advanced logic devices1–3. However, these features also pose
challenges for realizing high-performance field-effect transistors
(FETs) using standard fabrication processes. One key issue is the
high contact resistance. Charge carriers transport across metal-
semiconductorinterfacesviadiffusion,thermionicemission,ther-
mionic field emission, and pure field emission (tunneling),
dependingonthebarrierheightandwidthattheinterface4.Insili-
con (Si) technology, ion implantation is commonly employed to
heavily dope the regions beneath contacts, narrowing the barrier
and facilitating low-resistance tunneling contacts5. Nevertheless,
the high-energy impacts involved in this process can irreversibly
damagethecrystalstructureof2Dmaterials6,7,renderingitunsui-
tablefor2Ddevices.

Fromtheperspectiveofbarrierheight,simplyselectingametal
with work function matching the semiconductor’s band edge (i.e.,
metalswithlow/highworkfunctionsforn/p-typecontacts)isinsuffi-
cient to achieve ohmic contact. This is because metal-induced gap
states(MIGS)and/ordefectstatesatthecontactinterfacecanpinthe
actual Fermi level within the band gap, resulting in a high charge
injectionbarrierandaseveredeviationfromtheSchottky-Mottrule8,9.
One might expect that 2D semiconductors could avoid this issue
because of their dangling-bond-free van der Waals (vdW) surfaces.
However,interactionsinvolvingthedorbitalsbetweenthetransition
metalatomsintransitionmetaldichalcogenides(TMDs)andelectrode
metals lead to serious MIGS10,11. Additionally, lattice damage on
atomicallythin2Dbodiesduringmetaldepositionfurtherexacerbates
Fermilevelpinning12,thusdegradingcontactperformance.Recently,
significantprogresshasbeenmadeinn-type2Dsemiconductorsusing
semimetal contacts.With energyalignments,suppressed MIGS,and
moderateevaporationtemperatures,bismuth(Bi)andantimony(Sb)
have shown contact performance surpassing even advanced Si
technologies8,9.

In contrast, progress in p-type 2D FETs has lagged far behind,
primarily for two reasons. First, achieving p-type ohmic contacts
requirestheuseofhigh-work-functionmetalssuchasgold(Au),pla-
tinum(Pt),andpalladium(Pd).Theseheavymetalstendtogenerate
intensethermalradiationduringdeposition12;theirhighmomentum
resultingfromhighatomicmasstransferssubstantialkineticenergyto
thesurfaceatomsof2Dsemiconductors,exacerbatinglatticedamage
(Supplementary Fig. 1) and Fermi level pinning6. Although lowering
depositiontemperatureshasyieldedsomeimprovement,thereported
contactresistanceformonolayerWSe remainsashighas229kΩμm12.
2
Second, unlike n-type contacts, suitable high-work-function semi-
metalsforp-typecontactsarelacking.Whilealowcontactresistance
of0.75kΩμmonWSe hasbeenachievedusingSb/Ptcontact,itrelies
2
on a MoO capping layer for p-type doping and exhibits ambipolar
x
transportbehavior13.Therefore,developingacompatibleandscalable
strategy to improve p-type 2D FET contacts remains an urgent
challenge.

Here, we demonstrate the growth of metallic tellurium (m-Te)
withamonoclinicP2 phaseonMoTe,whichservesasapromising
1 2
p-type electrical contact for 2D FETs. The nearly perfect match of
interplanar/atom spacing between m-Te (021) and MoTe (1100)
2
planesenablesthestabilizationofm-Teunderambientconditions.The
interfaceisatomicallysharpwithavdWgapof0.162nm(surfaceto
surface)/0.332nm (atom to atom). First-principles calculations indi-
catethattheworkfunctionofm-Teisbasicallyalignedwiththevalence
bandmaximumofMoTe withmildMIGSandanegligibletunneling
2
barrier.Besides,m-Tep-dopestheunderlyingMoTe andcompensates
2
foritstelluriumvacancies,therebyenhancingp-typecharacteristics.
The m-Te-contacted bilayer MoTe transistors show a pure p-type
2
transportbehaviorwithalowcontactresistanceof1.6kΩμm,anon-
statecurrentofupto124μAμm-1,andamaximumon/offratioof107.
Theseparametersareamongthehighest-performancep-type2DFETs
reportedtodate.Ourworkpresentsapromisingdirectionforopti-
mizingcontactsof2Dsemiconductorsviain-situmetallicchalcogens
growth.

Results
Mainconceptofm-Teforp-typecontactsof2DFETs
Thekeytoachievinglow-resistancep-typecontactsfor2DFETsliesin
identifyingcontactmetalswithalignedenergylevelsandaweakFermi
pinningeffect.Here,weproposeanm-Teasaneffectivep-typecontact
for2HMoTe .MoTe isanambipolar2Dsemiconductorthatexhibits
2 2
p-typedominatedtransportpropertiesthroughcontactandthickness
engineering14. As a transition metal chalcogenide (TMD), each vdW
layerofMoTe consistsofaMoatomiclayersandwichedbetweentwo
2
Teatomiclayers(Fig.1a).EachMoatomexhibitsatrigonalprismatic
coordinationwithsixsurroundingTeatoms,formingtriangularchal-
cogenprismsatbothends.Thesestructuralunitsestablishaperiodic
vdW surface potential landscape (Fig. 1b). The lowest and second-
lowestenergypositionsarelocatedabovethecentersofhexagonal
hollow sites and directly above the Mo atoms, respectively, exhibiting
aperiodicitythatmatchestheequilibriumvdWinteractionradiusof
chalcogen atoms (Fig. 1a, b). This unique configuration enables the
controlled introduction of an additional metallic chalcogen layer15.
Given that the fully filled d-orbitals of chalcogens can alleviate the
possibilityofMIGSgeneration10,thisinducedmetallicchalcogenlayer
hasthepotentialtoserveasagoodelectricalcontactfortheTMDs.
ElementalTetypicallyadoptsatrigonalphaseconsistingofhelical
chains along the c-axis (P321 or P3 21 spacegroups, depending on
1 2
chirality), and has a band gap of 0.33eV under ambient conditions
(SupplementaryFig.2).However,underhighpressure(~45kbar),Te
transformsintoamonoclinicmetallicphasewithaspacegroupofP2
1
(Fig.1c,d,andSupplementaryFig.3)16,17.Thisphaseexhibitsalayered,
buckled structure resembling black phosphorous but lacks its
armchair-chain configuration.Instead,eachTeatomformscovalent
bonds with four neighbors within zigzag (020) planes, which are
stackedtogetherbyweakvdWforce(thedetailedunitparameterscan
befoundinSupplementaryFig.3e,f).

Notably, the interplanar spacing of m-Te (021) planes matches
thatof2HMoTe (1100)planes,withalignedunitsizes(Fig.1a,c).Thus,
2
2HMoTe canbepotentiallyemployedasanaturaltemplateform-Te
2
growth.Moreover,m-Tehasaworkfunctionslightlybelowthevalence
bandminimum(VBM)of2HMoTe 18,renderingitapromisingp-type
2
contactforMoTe FETs(Fig.1d).
2

Structureandmechanismofm-Teforp-typecontactsof2DFETs
15/80nm Te/Au contacts were deposited on MoTe following the
2
abovehypothesis,with15nmTeservingasaholeinjectionbufferlayer
(seeMethods).ThesurfacepotentialinductioneffectofMoTe was
2
firstverifiedbyscanningelectronmicroscopy(SEM)characterization
oftheTebuffermorphology(SupplementaryFig.4).TheTefilmshows
atexturedmorphologywiththreedominantorientationsonMoTe
2
with different thicknesses (Supplementary Fig. 5), which is distinct
from the randomly distributed spherical clusters on silicon dioxide
(SiO ),indicatingthepossibilityofvanderWaalsorientedgrowth19,20.
2
The interface structure of Te/MoTe was further investigated
2
usingcross-sectionalhigh-angleannulardark-fieldscanningtransmis-
sionelectronmicroscopy(HAADF-STEM)(Fig.2a,bandSupplemen-
taryFig.6).TeformscleanandatomicallysharpvdWcontactswith
MoTe ,showinganinterfacialspacingof0.162±0.01nm(surfaceto
2
surface)/0.332±0.01nm(atomtoatom)(Fig.2b)—smallerthantypical
vdWgapsintemperature-controlleddeposition12ortransfercontacts6.
The interplanar distances of Te and MoTe along the interface are
2
0.310nm and 0.316nm, corresponding to P2 Te (021) planes and
1
MoTe (1100)planes,respectively(denotedbythetopblueandbot-
2
tom orange lines in Fig. 2b). The lattice mismatch, defined as
jdð021Þ (cid:2)dð(cid:1)1100Þ j=dð(cid:1)1100Þ,isonly~1.90%.Moreimportantly,sinceP2
1
Te reciprocalprimarycellisshowninSupplementaryFig.7e;UPSresults
are shown in Supplementary Fig. 11d), consistent with previous
reports16, fulfilling the fundamental requirement for electrical con-
tacts.Inaddition,theKelvinprobeforcemicroscopy(KPFM)resultsin
SupplementaryFig.10indicatethattheelectricpotentialofm-Teis
higher thanthat of MoTe . The potential differencebetween m-Te/
2
MoTe heterostructure and MoTe is approximately 45meV. UPS
2 2
resultsinSupplementaryFig.11a-cindicatetheworkfunctionofm-Te/
MoTe heterostructureis4.57eV,largerthantheFermileveloffree-
2
standingMoTe (4.3eV),confirmingthepositivechargetransferfrom
2
m-TetoMoTe .Thebandoffsetofm-Te,2HMoTe andm-Te/MoTe
2 2 2
was further investigated by first-principles calculations in Supple-
mentaryFig.11e.

Afterincontactwithm-Te,thedensityofstates(DOS)ofMoTe
2
(Fig. 3b, lower panel)exhibits minor modifications compared to its
pristinecounterpart(Fig.3b,upperpanel),instarkcontrasttoTMD/
traditionalmetalcontacts(suchasAu,In,Pt,Pd)21,wherehighdensity
ofMIGSappearswithinthebandgaps.Thealleviationofin-gapMIGSin
thecaseofm-TecontactindicatesalowerpossibilityofFermi-level
pinning. We zoomed in on DOS of the band gap in Supplementary
Fig.12andfoundthatthebandgapofMoTe incontactwithm-Te
2
becomesnarrowerthanthatofthepristineone,andthemetal-induced
statesliewithinthebandasanextensionofbandedge.Specifically,the
valencebandedgeofTe-contactedMoTe composedmainlyofMod
2 z2
andTep bendsshiftsupwardscomparedwithpristineMoTe ,andthe
z 2
conductionbandedgeofitcomposedmainlyofTep shiftsdown-
z
wards.Asaresult,theFermilevel(E )oftheheterojunctionapproa-
F
ches the VBM of MoTe, accompanied by electron depletion of it
2
(Fig.3candSupplementaryFig.11f).Theaboveclearlydemonstrates
thep-typedopingeffectofm-TeonMoTe ,whichremainsrobusteven
2
inthepresenceofdonor-likeTevacanciesinMoTe asshowninFig.3c
2
(defectdensities:3.281×1013cm-2and6.562×1013cm-2corresponding
to one vacancy and two vacancies per supercell, respectively) -a
commonoccurrenceinpracticalMoTe samples22.
2
Furthermore, Te exhibits a tellurium-vacancy compensation
effecton MoTe .TheDOSanalysisshowsthattheenergyofdefect
2
states shifts toward the VBM with reduced density after
heterostructure formation (Supplementary Fig. 13a, b), facilitating
electron acceptance and enhancing p-type characteristics. Electron
spinresonance(ESR)measurementsat92Kprovidedirectevidenceof
this compensation effect, showing diminished Te-vacancy-related
resonance (g≈2.004) following Te deposition23 (Fig. 3d). This com-
pensation stems from interfacial charge transfer enabled by the
favorablebandalignmentbetweenm-TeandMoTe.
2
Besides,thetunnelingbarrierbetweenm-TeandMoTe wascal-
2
culatedtopossessawidth(w)of1.27Åandaheight(Φ)of2.95eV
t t
-a
(SupplementaryFig.11g),bothsmallerthanthoseofsemimetal/MoS
2
n-type contacts8,9. These results theoretically support the favorable
conditionsofm-Teasp-typecontactsofMoTe .
2
Thep-typedoping effectofm-TeonMoTe wassystematically
2
verified through multiple characterizations. Raman spectroscopy
revealed a uniform ~1.5cm−1 blueshift in the A mode of m-Te-
1g
contacted bilayer MoTe (Fig. 3e, f and Supplementary Fig. 14a, b),
2
confirmingmoderatep-doping,whiletheunchangedE modeindi-
2g
catednegligibleinterfacialstrain.Notethatnowideningoccurredof
theA fullwidthathalfmaximum(FWHM)(SupplementaryFig.14c,
1g
d),distinctfromPt/Pd-contactedMoTe (SupplementaryFig.1),
2
indicatingnegligiblesurfacedamageofm-TecontactedMoTe .TheA
2 1g
peakevenbecamenarrowerafterTedeposition.Thismightberelated
tothecompensatoryeffectwementionedabove.Besides,X-raypho-
toelectronspectroscopy(XPS)measurementsdemonstrateconsistent
180meVredshiftsinbothMo3d andMo3d peaks(Fig.3g),with
3/2 5/2
analogousshiftsobservedinm-Te3d andTe3d peaks(Supple-
3/2 5/2
mentaryFig.15),collectivelyrevealingaloweringoftheFermilevel
whenMoTe isincontactwithm-Te24–26.KPFManalysisfurthercor-
2
roborated these findings, showing a significant surface potential
reductioninTe-contactedregions(SupplementaryFig.16).
Furthermore, we analyzed the interaction between interfacial
atoms based on the results of energy loss spectroscopy (EELS) and
crystalorbitalHamiltonpopulation(COHP)calculations.IntheEELS
experiment,weobservedthattheedgeshape,i.e.,thecurveslopeof
interfacialMoTe Layer1inEELSprofile(SupplementaryFig.17)ofthe
2
m-Te/MoTe scenarioisunparalleltothoseofthelayersawayfromthe
2
interface,whichreferstochangedelectronicstructures,quitediffer-
entfromtheparallelscenarioinvanderWaalsPtcontact12.Thus,the
p-type doping and defect compensation effects brought by m-Te
create distinctelectronic environmentsatthe interface,makingthe
first-layerTeinMoTe differentfromthatoftheinnerparts.However,
2
noobviousenergyshiftwasobserved,indicatingthatnonewbonds
wereformedattheinterface.Inaddition,tofurtherassesstheinter-
facial Te–Te interaction strength, −COHP (minus Crystal Orbital
Hamilton Population) curves and −ICOHP (integrated −COHP) were
furthercomputed.InSupplementaryFig.18,the−COHPcurvesshow
thattheTe–TeinteractionismuchweakerthantheMo–Teinteraction
within2HMoTe andtheTe–Teinteractionwithinm-Te,manifesting
2
−COHPvalueshoveringclosetozero,withonlysmalloscillations.This
sharp contrastis then quantified by −ICOHP values,i.e.,0.15eV per
bondforinterfacialTe–Tepairs,2.23eVperbondforMoTe Mo–Te
2
pairs,and1.12eVforTe–Tepairsinm-Te.

High-performanceMoTe p-FETswithmetallicTecontacts
2
Finally, we investigate the electrical performance of bilayer MoTe
2
FETs employing m-Te as contacts. The analysis of the thickness of
MoTe can be seen in Supplementary Fig. 19 and Supplementary
2
Fig.20.Figs.4a,bshowthetransfercurve(i.e.,source-draincurrentvs.
gatevoltage,I -V )andoutputcurves(i.e.,source-draincurrentvs.
ds gs
source-drainvoltage,I -V ),respectively.Notably,thedeviceexhibits
ds ds
primarily p-type transport behavior with excellent linearity at full-
rangegatevoltages(SupplementaryFig.21)andattemperaturesfrom
100Kto300K(SupplementaryFig.22a–k),confirmingtheformation
of high-quality p-type ohmic contacts. Furthermore, the devices
maintainedstabletransfercharacteristicsafter10monthsofstorage,
provingthelong-termreliabilityofm-Tecontactsforp-typeMoTe
2
FETs(SupplementaryFig.22i);andthem-Tecontactsremainstable
after 300°C annealing and 103s prolonged operation, as shown in
SupplementaryFig.23andSupplementaryFig.24.Deviceswithvari-
ablechannellengths(L )werefabricated(Fig.4cinset)onuniform
ch
MoTe stripsandthetransfer-lengthmethod(TLM)wasemployedto
2
quantitativelydeterminethecontactresistance(R ).Itisworthnoting
C
thatthecontactresistancecangenerallybedividedintotheintrinsic
partthatcannotbecontrolledbythegateandthejunctionpartthat
canbecontrolledbythegate27.Bothofthesepartscontributetothe
contact resistance. Although the TLM method cannot provide the
origin and mechanism of the contact resistance, it can still offer a
benchmark reference forthe totalinterface resistance. Remarkably,
thebilayer MoTe devices showR aslow as 1.6kΩμm ata carrier
2 C
density(p )of~1.0×1013cm-2(Fig.4c),withconsistentperformance
2D
observedinmultipledevices(SupplementaryFig.25).
Theexcellentp-typecontactpropertiesoriginatefromtheideal
bandalignmentbetweenm-TeandMoTe ,asconfirmedbySchottky
2
barrier analysis. Unlike conventional Schottky contacts that exhibit
negativeslopesinArrheniusplots(ln(I /T1.5)vs.1,000/T,whereTis
ds
temperature), m-Te/MoTe FETs consistently show positive slopes
2
whenthedeviceisturnedon,providingdirectevidenceforbarrier-free
hole injection (Fig. 4d, Supplementary Fig. 26 and Supplementary
Fig.27).ForthedetailsoftheArrheniuscurves,pleaserefertoMeth-
ods.TheabsenceofaneffectiveholebarriersuggestsweakFermi-level
pinning,whichcanbeattributedtothefollowingfactors:(1)MoTe
2
remains intact after Te evaporation, ruling out the introduction of
interfacialdefectstates;(2)ThevdWgapbetweenm-TeandMoTe
2
minimizestheoverlapbetweentheorbitalsofm-TeandMoTe andthe
2
MIGSinducedbym-Tearenegligible;(3)Thetellurium-vacancycom-
pensation effect of m-Te above MoTe can suppress the defect-
2
inducedgapstates.
A130nmL bilayerMoTe FETwasfabricatedtofurtherincrease
ch 2
theon-statecurrent(I ).Thedeviceshowsgoodlinearoutputcurves
on
withan I achieved124μAμm-1 ataV of-1V(Fig.4e).Figure4f
on ds
presents the statistics of I measured on 25 MoTe devices with
on 2
channellengthatap ofaround1×1013cm-2,indicatinggoodrepeat-
2D
abilityofthehigh-performancep-typecontactsusingmetallicTe(see
detailedcharacteristicsofeachdeviceinSupplementaryFig.28).
We finally benchmark our devices with the state-of-the-art 2D
p-type FETs based on MoTe (blue) and undoped WSe (orange)
2 2
(Fig.4g,h).Giventhatfew-layer2Dsemiconductordevicesgenerally
exhibit lower performance compared to those based on multilayer
counterparts,wedistinguishthedatabetween1-2layers(solid)and
multilayerdevices(hollow).ItisworthnotingthatallMoTe samples
2
usedinthisworkwereexfoliatedfrombulkcrystals,whicharecloser
to intrinsic semiconductors compared to those grown by chemical
vapordeposition(CVD).Ourdevicesyieldoneofthehighestcurrent
densities among MoTe transistors and an on/off ratio reaching
2
~1.2×107, which is comparable to 100 nm-channel WSe /Pt devices
2
(CVD-grown) on 5nm SiO 28. Although the NO doping method has
2
improvedthep-typecontact,thethermalstabilityofwhichstillneeds
tobeenhanced29,30.Tothebestofourknowledge,theachievedcon-
tact resistance of 1.6 kΩ·μm represents one of the lowest reported
valuesforundopedmono-/bilayerp-typeMoTe .Comparedtometal
2
transfer or CVD-grown epitaxial approaches31,32, our direct thermal
evaporation ofTe offers superiorcompatibilitywith existing silicon
technologiessincethetransferprocessisomittedandthereisnoneed
toconsidertheetchingissueafterm-Tegrowth.AsshowninSupple-
mentaryFig.29,them-Tecontactstrategyalsohasthepotentialtobe
extendedtothefabricationofdevicesonlarge-scaleMoTe,facilitat-
2
ingsubsequentintegration.

Methods
Devicefabrication
Al O deposited on highly doped silicon through atomic layer
2 3
deposition(ALD)wasusedasaback-gatesubstrate.Theprocesswas
performedat150°Cwithagrowthrateof1.4Åpercycle.BilayerMoTe
2
samplesweremechanicallyexfoliatedfrombulkcrystalsandidentified
byopticalcontrast.BeforeexfoliatingMoTe,Al O substrateswere
2 2 3
cleanedbyO plasma(20sccm,30W,5s)toincreasetheexfoliation
2
yield. The 15/80nm Te/Au electrodes were made by electron-beam
lithography(EBL)andthermalevaporation.Then,MoTe FETswere
2
annealedat100°Cfor30mininaninertgasenvironmenttoenhance
thecontactperformance.
Wenoticedthatp-type2Dsemiconductorsaresensitivetoelec-
tronbeamlithography(EBL)accelerationvoltage,whichmayexplain
the persistent challenges in achieving high-performance p-type 2D
contacts. Although high acceleration voltage (100kV) enables high
resolution and good pattern fidelity (Supplementary Fig. 30a, d), it
simultaneouslybringsacertaindegreeofn-typedopingon2Dsemi-
conductors.AsshowninSupplementaryFig.30,bilayerMoTe FETs
2
with Te contacts exposed at 100kV exhibit nonlinear output and
n-dominatedbipolartransfercharacteristics.Tomitigatethiseffect,
weemployedalowaccelerationvoltageof10kVforalldevicefabri-
cation in this work, which effectively suppressed electron beam-
inducedn-typeinMoTe (Fig.4a,b).Moreover,thecontactareaswere
2
exposedusingabeamcurrentof150pAandanarealdoseof120inthe
systemtominimizethermaleffectsandchargeaccumulation33.
ForTLMdevices,MoTe waspatternedbyEBLandetchedtoabar
2
geometrybyreactiveionetchingwithCF andO plasma.Thesub-
4 2
sequentprocessingstepsarethesameasforothernormaldevices.
Notethattheprocessofaddingaprotectivelayeractuallypro-
longs the time that MoTe exposing to the air or introduces more
2
unstablesources,like water during the deposition of dielectrics. As
shown in Supplementary Fig. 31, we observed the performance
degradation even in multilayer devices after capping an additional
layerofAl O .Therefore,inthiswork,them-Te/MoTe FETsdidnot
2 2 3 2
employanyprotectivecappinglayers.

Thedepositionofm-Te
TheClausius-Clapeyron relationoftellurium’ssaturatedvaporpres-
surePandtemperatureTcanbewrittenas34:

lgPðtorrÞ=ð10:45±0:10Þ(cid:2) 8021±71 ,T<723K ð1Þ
T

Before evaporation, the chamber should be vacuumed to
1×10-5~1.8×10-5Pa. After starting to heat the tungsten boat, the
evaporation rate is controlled at 0.1Ås-1, and the chamber soon
reaches a stable pressure of about 2.3×10-5Pa (1.73×10⁻⁷ torr).
The “dynamic equilibrium pressure” here is used as the approx-
imation of the saturated vapor pressure of Te powder, then the
temperature of 466.0±6.1K in a tungsten boat can be obtained
bytheformula.15nmTewasdepositedontoMoTe in25minand
2
radiative heating of the 2D materials from the crucible during
metal evaporation was negligible. For Au deposition, the eva-
porationratewas0.2Ås-1.

Calibrationofcarrierdensity
TheholedensityofMoTe FETswasextractedaccordingto:
2
h= C ox V (cid:2)V ð2Þ
q th gs

Byevaporating200×200μm2padsofAuontheAl O substrates,
2 3
C (Fcm-2)wasobtainedbycapacitancemeasurementsusingKeysight
ox
1500andareanormalization.Accordingtothetransfercharacteristics,
the V of each device was extracted in the linear region when
th
V =0.1V:
ds
I =μC W ðV (cid:2)V ÞV ð3Þ
ds ox L gs th ds

Byfitting
I =aV +b, ð4Þ
ds gs
aandbweregained,so
V = (cid:2) b ð5Þ
th a

AfterobtainingC andV ,theholedensitywasderivedunder
ox th
certainV foreachdevice.
gs

Schottkybarrierextraction
Thethermionicemissioncurrentinjectedfromametalcontactintoa
2DchannelthroughaSchottkybarriercanbegivenbytheRichardson-
Dushmanequation:
φ
I =A*Tαexpð(cid:2) BÞ ð6Þ
thermo k B T

whereA∗istheRichardsonconstant,Tisthetemperature,k isthe
B
Boltzmann constant, and φ is the effective contact barrier height.
B
Consideringtheenergy-independentdensityofstatesofa2Dsystem,
αis3/2for2Dsemiconductors.WhenavoltageV isappliedacross
ds
the Schottky barrier, it modifies the barrier height and the carrier
injectionprocess.InaSchottky-barrierFET,thereverse-biasedcontact
accountsforthemajorityofthevoltagedropandplaysacriticalrolein
governing the transistor’s behavior. The drain current density
thermallyinjectedfromthemetalcontactintothe2Dchannelthrough
suchareverse-biasedSchottkybarriercanbeexpressedas:

I =A* 2d T1:5exp (cid:2) k φ B B T ½1(cid:2)expð(cid:2) k V B d T sÞ(cid:3) ð7Þ

WhenV »k T,Eq.(7)canbesimplifiedto:
ds B

I =A* 2d T1:5expð(cid:2) k φ B B T Þ ð8Þ
ds

Inthisregime,theeffectiveenergybarrierφ ataspecificV can
B gs
bedeterminedbyanalyzingtheslopeoftheArrheniusplots.Thisis
achievedusingthefollowingrelationship:

ln I ds = (cid:2)φ B +c ð9Þ
T1:5 k B T

Aswecansee,theArrheniusplotsofon-stateTe-contactedMoTe
2
FETsdisplayanoppositetrendtothethermionicemissionmodel(Eq.
(9)).Theabsenceofanegativeslopeimpliesthecontactbarrier-free
natureoftheTe–MoTe FETs.Itisworthnotingthatthetotalmea-
2
sured current is set by the series combination of contact-limited
injection and channel resistance, which arealtered by temperature-
dependent scattering mechanisms35, especially the latter one con-
sideringthatthechannellengthofthedeviceusedtoanalyzebarrieris
400nm, manifesting as temperature-dependent current in Supple-
mentary Fig. 26a. This causes the Arrhenius point to exhibit non-
linearityinSupplementaryFig.26b,c.Tomakethephysicalpicture
clearer, we analyzed the gate-modulated band diagram in Supple-
mentaryFig.27.Afterm-TeandMoTe contact,thebandoffsetatthe
2
interfaceisfixed.Sincetheworkfunctionofm-Teishigherthanthe
VBMofMoTe 2 ,asgatevoltageschange,thechannelpartofMoTe 2 can
bealignedwithrespecttothem-Tewhenthepositivegatemodulation
reachesacertainpoint,ratherthantheconventionalflatbandcondi-
tion. The “barrier” energy of this pseudo flat-band condition might
correspond to the energy required for holes to escape from the
potentialwellatthecontactinterface.

Measurements
Transportcharacteristicsweremeasuredbyapplyingvoltageswiththe
Keysight 1500 semiconductor parameter analyzer system. The low-
temperaturemeasurementswereperformedinavacuumprobesta-
tionwithliquidnitrogenandatemperaturecontroller.
ESRwastestedbyBruckerEMXplus-9.5/12.AmassofMoTe was
2
exfoliatedtoa3×7mmSiO /Sisubstrateandslidtothebottomofthe
2
tubeforESRtestat92K.Afterthetest,MoTe /SiO /Siwasvacuumized
2 2
immediatelyandreadyfor15nmTeevaporation.ThentheESRtestof
Te/MoTe /SiO /Siwasconducted.
2 2
Raman data were collected by 633-nm laser excitation focused
througha×100objectivelensusingRenishawinVia-Qontor.XPSwas
performedusingtheThermoScientificEACALAB250Xi.Atomicforce
microscopy and Kelvin probe force microscopy (KPFM) were per-
formedusingtheBruckermultimode8HR.ToconductKPFM,15nmTe
wasevaporatedontoexfoliatedMoTe onPDMS.Then,Te/MoTe was
2 2
transferredtoaAusubstratewithMoTe ontheupperside.
2

DFTcalculations
DFT calculations in this work were performed using the Vienna Ab
initio Simulation Package (VASP)36,37. The Perdew–Burke–Ernzerhof
(PBE) functional within the generalized gradient approximation
(GGA)37 wasused to describe the exchange-correlation interactions.
Theprojector-augmentedwave(PAW)38methodwasadopted,andthe
kinetic energy cutoff was set to 400eV. The Brillouin zone was
sampled using the Monkhorst–Pack method39 with a k-point mesh
density of 0.03Å⁻¹. The DFT-D340 correction of Grimme with
Becke–Johnson(BJ)damping41wasusedtodescribetheinterlayervan
derWaalsinteractions.Allstructureswerefullyrelaxed.Theforceand
energyconvergencecriteriaweresetto10-2eV/Åand10-5eV,respec-
tively. The heterostructure was modeled using a slab structure. A
vacuumlayerof20Åwasaddedalongthezdirectiontoavoidinter-
actionsbetweenperiodicimages.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "This work introduces a novel and practical method to address the long-standing challenge of forming high-performance p-type contacts in 2D MoTe₂ transistors. By thermally evaporating elemental tellurium onto bilayer MoTe₂, the Te atoms spontaneously crystallize in situ into the monoclinic P2₁ metallic phase (m-Te), driven by favorable lattice matching and interfacial energetics.\nThis process forms an atomically sharp van der Waals epitaxial interface with only ~1.9% lattice mismatch, effectively suppressing metal-induced gap states (MIGS) and Fermi-level pinning, while also enabling hole doping and Te vacancy compensation. The resulting devices exhibit low contact resistance (~1.6 kΩ·μm), high on-current (~124 μA/μm), and an on/off ratio of ~10⁷, with stable performance maintained over 10 months. This in situ chalcogen epitaxy via evaporated Te offers a promising and potentially CMOS-compatible approach toward low-barrier p-type contacts in 2D MoTe₂.\nWhile the results are impressive, I still have a few questions regarding the following:\n1. Although epitaxy m-Te growth on MoTe2 was claimed, the only evidence of epitaxy growth is based on local TEM or SAED results at nm scales. Some larger area analysis is required. For example, by showing the TEM images in Fig. 2a along the x direction on a larger scale, or SAED from multiple points in a large area. Otherwise, local alignment of few atoms on a small scale cannot be called epitaxy in my opinion. In fact, I assume the m-Te is polycrystalline. What is the grain size?\n2. In the Introduction, the authors attribute potential 2D material damage to the heavy atomic mass and high kinetic energy of Pt/Pd during deposition. However, no structural or spectroscopic evidence is provided to confirm that evaporated Te avoids similar interfacial damage. Without direct comparison or surface analysis (e.g., Raman, AFM), the claim that Te enables a gentler vdW contact remains speculative.\n3. In Fig. 4, the authors extract contact resistance (~1.6 kΩ·μm) using TLM measurements from devices with channel lengths ≥ 0.3 µm. However, according to Ber et al. [1], the transfer length (Ltk) in atomically thin semiconductors is often ~240 nm, and lateral junction resistance (Rjun)—not captured in the TLM model—can significantly influence the extracted value. Relying only on long-channel devices may underestimate the true contact resistance due to neglected lateral injection effects.\n4. In Supplementary Fig. 4, panel g lists the structural parameters for “monoclinic tellurium/MoTe₂”, but panels e and f correspond to trigonal Te on MoTe₂, as implied by the caption. Could the authors clarify whether panel g actually refers to the trigonal Te/MoTe₂ structure? If so, the heading in panel g may need correction to avoid confusion.\n5. In Supplementary Fig. 11a, five layers are marked for EELS, yet only four are shown in Fig. 11b. Could the authors clarify why Layer 5 was omitted? Additionally, the Te M₄-edge spectra appear largely similar across layers, with only minor variations that may fall within experimental noise. To substantiate the claim of \"distinct electronic environments,\" could the authors provide quantitative analysis or clarify the significance of these spectral differences?\nIn summary, this work presents a promising strategy for p-type 2D contacts. Addressing the points above would further support the authors’ claims and improve clarity.\n[1]: Ber, Emanuel, et al. \"Uncovering the different components of contact resistance to atomically thin semiconductors.\" Advanced Electronic Materials 9.6 (2023): 2201342.", "reviewer_2": "high performance p-type transistors is fundamentally crucial for atomically monolithic thin TMDs-based next beyond-silicon electronics via the common CMOS technology. This manuscript demonstrates a novel epitaxial growth strategy of metallic-phase tellurium (m-Te) on MoTe2 via evaporation as an efficient p-type contact. Through the comprehensive investigation, monoclinic metallic P21 Te which typically requires high-pressure synthesis can be obtained through simple evaporation with the (021) plane aligned to the MoTe2 (100) plane. Through this novel contact architecture, the authors claim that metallic-Te is feasible for the efficient p-type contact of MoTe₂ transistors with near-barrier-free hole injection. Ultimately, the authors benchmark the bilayer MoTe2 transistor performance with the current reports. We consider the epitaxial growth of m-Te on MoTe2 (100) plane was systematically investigated and such strategy offers another process selection to achieve good p-type contact quality of MoTe2 transistors. However, some crucial concerns of the actual feasibility of m-Te as a p-type contact for MoTe2 transistors should be addressed before its consideration for the publication in Nature Communications as followed:\n1.The authors have performed systematic investigation of vdW epitaxy of m-Te on MoTe2, and the results are impressive and intriguing. In this section, the first concern is whether chemical bonding occurs during the m-Te deposition on MoTe2 film, which requires more experimental verification such as XPS characterization. The vdW epitaxial growth is quite important for the contact quality and the following discussion. Secondly, as the authors claimed, the elemental Te generally exhibit a semiconducting trigonal phase under ambient conditions. We wonder except for the lattice match consideration, whether deposition conditions such as temperature would impact the m-Te phase formation. Whether the authors have verified how to control and optimize the M-Te phase formation? In other words, whether semiconducting Te film can be grown in MoTe2 nanosheets and/or the substrate such as SiO2/Si in other area? Thirdly, how to verify the possible defects introduction such as the damage to the MoTe2 channel during the deposition process, which is commonly unavoidable for traditional metal thermal deposition? Ultimately, the crucial concern in this section relies in the insufficient information about the m-Te film. Although the authors show the crystal structure and XRD pattern of m-Te film, however, its vital material characteristics for suitable contact electrodes should be further clarified. For example, the resistivity-temperature relationship should be given to verify its metallic nature except for the electronic structure theoretical calculation. The crucial factor of work function should be also verified by UPS, and the band alignment between m-Te and MoTe2 should be also verified by KPFM characterization;\n2.The authors have claimed that the m-Te/MoTe2 interface enables barrier-free hole injection, however, such claim is lack of crucial evidences. Firstly, in line 205-211, the work function of m-Te was determined as 4.65 eV, which is lower than the VBM of MoTe2. Such DFT theoretical calculation requires further experimental verification. We understand that these values are easily underestimated by theoretical calculation, however, the VBM of MoTe2 has been well verified as ~4.8-5.0 eV experimentally. In this regard, the direct band alignment should be supplemented. Secondly, In Fig. 3b, the MIGS should be given with the magnified PLDOS in the bandgap. We doubted what is the special features of m-Te can indeed alleviate the MIGS, which enables the m-Te differing from other contact metal electrodes. The authors should clarify that. Thirdly, for the electrical performance of the contacts, more crucial evidences should be supplemented. For example, in Fig. 4b, although the m-Te/MoTe2 contact shows linear output characteristics in room temperature, the similar output characteristics at low temperature should be also clarified, since thermionic emission was suppressed at low temperature. Meanwhile, the linear characteristics in Fig. 4b is reasonable in the range of 0V to -20V, because the device is always operated in “on” state in this gate range from Fig 4a. In this regard, the gate voltage should be given from higher than 20V to -20V. Similarly and vitally, the authors plotted an Arrhenius curve in Fig. 4d and claimed that positive slopes across different gate voltages thus providing direct evidence for barrier-free charge injection. However, the device is always operated in “on” state in this gate voltage range from -10V to -25V, implying the bend bending of MoTe2 channel and barrier-free for hole injection. The authors should provide the extracted barrier height at different gate voltage, thus to obtain the barrier height at flat-band. Another direct experimental evidence for the barrier-free hole injection lies in the increased on-state current with the decreased temperature, and the Ids-Vds curves as function of temperature should be also clarified;\n3.Ultimately, the authors benchmark their devices with the state-of-the-art 2D p-type FETs based on MoTe2 (blue) and undoped WSe2 (orange) (Figs. 4g, h). Firstly, to our best known, p-type WSe₂ transistors have already achieved Rc as low as 0.041 kΩ·μm (Science 388, 1183–1188 (2025)) and on-current up to 1.5 mA/μm (Nat. Electron. 5, 497–504 (2022)). The comparison with WSe₂ should be more cautious. Meanwhile, recent investigations such as NO surface doping (Nat. Commun. 16, 4160 (2025)), semimetal contacts (ACS Appl. Mater. Interfaces 17, 25518–25525 (2025); Nat. Commun. 14, 4747 (2023)) etc. have also shown excellent p-type electronic performance. The authors should also benchmark these investigations;\n4.Some more experimental details should be also supplemented. For example, for device fabrication, the exfoliated MoTe2 nanosheets were adopted as the device channel. In such case, whether a large-scale M-Te film can be obtained? how to etch the unnecessary Te film selectively from the MoTe2 nanosheets and underlying substrate? How the etching process impact the quality of MoTe2 channel? Whether preferable growth of M-Te on the contact area is feasible? In Fig. 4, bilayer MoTe₂ transistors were investigated. Further supporting evidence such as Raman, AFM step height, or optical contrast calibration should be provided to verify its bilayer thickness. Meanwhile, for the device electronic characteristics, the SS values should be also given to further verify the contact quality and high-k dielectric/channel quality.", "reviewer_3": "This study by Zhu et al. aims to address the p-type contact challenge in 2D semiconductors by introducing metallic tellurium (m-Te) as a novel contact material. Using van der Waals (vdW) epitaxy, the authors grew monoclinic metallic Te (m-Te) on 2H-MoTe2, achieving close lattice matching and stable bonding without high-pressure conditions. Since MoTe2 can be tuned to be p-type and shares structural compatibility with Te, the deposited Te atoms align to form a metallic layer with ideal band alignment and minimal MIGS, enabling low-resistance, high-quality p-type contacts. This Reviewer believes that the study offers a new direction for addressing the p-type contact challenge in 2D electronic devices, despite some practical constraints. However, for the publication of this study, it is considered necessary to address the following points and overcome the associated limitations.\n1) The key to achieve vdW epitaxy seems to be matching the m-Te (021) planes with the 2H-MoTe2 (-1100) planes, with aligned unit cell dimensions. How universal is this growth approach via evaporation, and does it have a limited growth window?\n2) Could it be that the desired vdW epitaxy occurred only under specific evaporation conditions on the bilayer MoTe2 film? To verify this, this Reviewer suggest examining whether the m-Te layer exhibits vdW epitaxy on MoTe samples of different thicknesses, which can be readily obtained via mechanical exfoliation.\n3) These results were mainly obtained for exfoliated bilayer MoTe2, with no discussion of how they might differ for monolayer samples. Since contact properties in 2D materials often degrade as the layer number decreases, verifying the method on monolayer MoTe2 would help clarify its limitations and applicability. If necessary, contact resistance measurements could be performed, and the use of a gate metal or auxiliary layers could be considered.\n4) Although the study reports stable properties after 10 months of storage, additional verification is needed under thermal and current stress. Since tellurium can resublime at elevated temperatures or interdiffuse with metals, it is worthwhile to assess whether m-Te contacts remain stable after thermal annealing or prolonged operation, and explore reliability enhancements through protective layers if necessary.\n5) The authors demonstrated excellent p-type FET performance at a channel length of ~130 nm. However, most studies report device performance at micrometer-scale channel lengths achievable via photolithography. For a clearer comparison, it would be helpful if the authors could also provide such data for their samples, if available."}, "author_response": "We thank all the reviewers for their valuable comments. They have helped us to prepare a better\nmanuscript. Point-by-point response to reviewers’ comments follows.\nResponse to Reviewer #1:\nComments: This work introduces a novel and practical method to address the long-standing\nchallenge of forming high-performance p-type contacts in 2D MoTe transistors. By thermally\n2\nevaporating elemental tellurium onto bilayer MoTe , the Te atoms spontaneously crystallize in\n2\nsitu into the monoclinic P2 metallic phase (m-Te), driven by favorable lattice matching and\n1\ninterfacial energetics.\nThis process forms an atomically sharp van der Waals epitaxial interface with only ~1.9%\nlattice mismatch, effectively suppressing metal-induced gap states (MIGS) and Fermi-level\npinning, while also enabling hole doping and Te vacancy compensation. The resulting devices\nexhibit low contact resistance (~1.6 kΩ·μm), high on-current (~124 μA/μm), and an on/off ratio\nof ~107, with stable performance maintained over 10 months. This in situ chalcogen epitaxy via\nevaporated Te offers a promising and potentially CMOS-compatible approach toward low-\nbarrier p-type contacts in 2D MoTe .\nComment 1: Although epitaxy m-Te growth on MoTe was claimed, the only evidence of epitaxy\n2\ngrowth is based on local TEM or SAED results at nm scales. Some larger area analysis is\nrequired. For example, by showing the TEM images in Fig. 2a along the x direction on a larger\nscale, or SAED from multiple points in a large area. Otherwise, local alignment of few atoms\non a small scale cannot be called epitaxy in my opinion. In fact, I assume the m-Te is\npolycrystalline. What is the grain size?\nResponse 1: Larger-scale cross-sectional TEM images are shown in Figure R1. It can be seen\nthat the interface between Te and MoTe is a van der Waals interface. Note that Te atoms have\n2\nthree different orientations on MoTe . In terms of probability, there is a 2/3 portion of the images\n2\nin which the atoms of MoTe and m-Te cannot be clearly observed simultaneously. The m-Te\n2\non MoTe is indeed polycrystalline. However, as shown in Figure R2 (Supplementary Fig. 4a-\n2\nc), Te has three dominant orientations on MoTe , and the size of each domain is approximately\n2\n150 nm, distinct from its amorphous morphology on SiO . Besides, from cross-sectional TEM\n2\nimages at different points, when the zone axis of Te is well-aligned to the same projection of\n2H MoTe <101̅0> along which FIB cut (so that the atoms of both can be clearly seen), regular\n2\nrows of Te atoms appear at the interface. Combining the orientated configuration and atom\n1\nalignment, in our original manuscript, we considered m-Te and 2H MoTe to be an epitaxial\n2\nrelationship.\nAs the reviewer mentioned, the atom alignment is local, and each 150-nm domain is\ncomposed of polycrystalline tellurium with the same orientation, so we acknowledge that it is\nnot rigorous to regard the acquisition of m-Te as epitaxy. However, we still believe that m-Te\nhas the potential to be epitaxially grown on 2H MoTe according to the features we mentioned\n2\nabove, and other chalcogens could be epitaxially grown on other TMDs according to Figure R3\n(Supplementary Fig. 9), which have been added to our future research plan.\nBased on this comment, we have added Figure R1 as Supplementary Fig. 6 in the revised\nSupplementary Information and corrected the statement about ‘van der Waals epitaxy’ to ‘van\nder Waals oriented growth’ in the revised manuscript.\na c d e\nf g h\nb\ni j\n5 n m ~0.33 nm ~0.33 nm\nFigure R1. Cross-sectional scanning transmission electron microscopy (STEM) images\nof Te/MoTe at different regions. a, b, Scale bar, 2 nm. c-j, Scale bar, 1 nm.\n2\n2 2\nThe morphology of tellurium on MoTe and SiO is conspicuously different, the latter being\n2 2\namorphous spheres (a, right), while tellurium has three orientations on MoTe (b,c).\n2 2\nthe crystal parameters of Se allotropes, the space group of Se epitaxially grown on WSe is R3̅.\nstructure of the Se ring.\nheavy atomic mass and high kinetic energy of Pt/Pd during deposition. However, no structural\nor spectroscopic evidence is provided to confirm that evaporated Te avoids similar interfacial\ndamage. Without direct comparison or surface analysis (e.g., Raman, AFM), the claim that Te\nenables a gentler vdW contact remains speculative.\nResponse 2: We acknowledge the suggestion. Per the reviewer’s request, we deposited 5 nm\nTe, 5 nm Pt and 5 nm Pd onto three MoTe samples separately and scanned Raman spectra by\n2\na 633-nm laser for pristine and as-deposited MoTe for comparison (Figure R4). Here, the full\n2\nwidth at half maximum (FWHM) is used to identify the crystal quality. The lower the ∆FWHM\n(the FWHM difference between before and after metal deposition) is, the less damage the metal\ndeposition causes. We noticed that for Pt/Pd-covered MoTe , a much broader ∆FWHM of A\n2 1g\npeak than that of the m-Te covered sample can be observed (Figure R4). The FWHM of the\nlatter even decreases, which might be related to the defect compensation we mentioned in the\n3\nmanuscript. We thus consider that m-Te causes less damage to MoTe than heavy metals like\nFigure R4 has been added as Supplementary Fig. 1 and Supplementary Fig. 14c, d.\nThe\ncorresponding contexts have been modified in the revised manuscript as “These heavy metals\ntend to generate intense thermal radiation during deposition; their high momentum resulting\nfrom high atomic mass transfers substantial kinetic energy to the surface atoms of 2D\nsemiconductors, exacerbating lattice damage (Supplementary Fig. 1) and Fermi level pinning.”\nin the introduction section, and “Note that no widening occurred of the A full width at half\n1g\nmaximum (FWHM) (Supplementary Fig. 14c, d), distinct from Pt/Pd-contacted MoTe\n2\n(Supplementary Fig. 1), indicating negligible surface damage of m-Te contacted MoTe . The\n1g\neffect we mentioned above.” on page 10.\nFigure R4. Surface damage analysis by Raman spectra. Raman spectra of pristine MoTe (a,\n2\nc, e) and Te/Pt/Pd-covered ones (b, d, f). The corresponding optical microscope images are in\nthe insets of a, c, e, respectively. Scale bar: 4 μm. Here, x represents the position of the A\nc 1g\npeaks, and w represents the FWHM.\nComment 3: In Fig. 4, the authors extract contact resistance (~1.6 kΩ·μm) using TLM\nmeasurements from devices with channel lengths ≥ 0.3 µm. However, according to Ber et al. [1],\nthe transfer length (L ) in atomically thin semiconductors is often ~240 nm, and lateral junction\ntk\n4\nresistance (R )—not captured in the TLM model—can significantly influence the extracted\njun\nvalue. Relying only on long-channel devices may underestimate the true contact resistance due\nto neglected lateral injection effects.\n[1]: Ber, Emanuel, et al. \"Uncovering the different components of contact resistance to\natomically thin semiconductors.\" Advanced Electronic Materials 9.6 (2023): 2201342.\nResponse 3: Thank you for providing an insightful article, in which the contact resistance was\ndivided into the intrinsic (R ) and ‘junction’ (R ) parts independent/dependent of the gate\nc-i jun\nvoltages [B. Emanuel et al. Adv Elect Materials 9, 6, 2201342 (2023)]. According to this article,\nthe contact resistance R (or R )extracted by TLM is in fact equal to the sum of R and R .\nc c-tot c-i jun\nIn other words, R extracted by TLM includes R . Through comparing R with R extracted\nc jun jun c-tot\nby TLM, this article concluded that R of their Ni-contacted MoS devices is dominated by\nc-tot 2\nR part (Figure R5). Therefore, if the 'true contact resistance' the reviewer mentioned was the\njun\nintrinsic contact resistance, TLM will overestimate it.\nAccording to recent research, a channel length ranging from 102 nanometers to several\nmicrometers is sufficient to provide an interface resistance that can serve as a benchmark\nreference [Y. Wang et al. Nature 610, 7930 (2022)]. And TLM method has been widely used to\nextract the contact resistances of devices based on traditional semiconductors like Ge, Si, GaAs,\nwith micrometer-range channel lengths (Dieter K. Schroder, Semiconductor Material and\nDevice Characterization).\nBased on this comment, we have included the discussion as “It is worth noting that the\ncontact resistance can generally be divided into the intrinsic part that cannot be controlled by\nthe gate and the junction part that can be controlled by the gate44. Both of these parts contribute\nto contact resistance. Although the TLM method cannot provide the origin and mechanism of\nthe contact resistance, it can still offer a benchmark reference for the total interface resistance”\nin the revised manuscript.\nc-tot jun, c-i\nAdv Elect Materials 9, 6, 2201342 (2023)]. Copyright © 2025 the Authors, licensed under a\nCreative Commons CC BY license.\nComment 4: In Supplementary Fig. 4, panel g lists the structural parameters for “monoclinic\ntellurium/MoTe₂”, but panels e and f correspond to trigonal Te on MoTe₂, as implied by the\ncaption. Could the authors clarify whether panel g actually refers to the trigonal Te/MoTe₂\nstructure? If so, the heading in panel g may need correction to avoid confusion.\nResponse 4: Thank you for the reminder. We are sorry for the typing mistakes. In original\nSupplementary Fig. 4 (now Supplementary Fig. 8), panels g and h indeed refer to trigonal Te\non MoTe . And we have made corrections to the revised Supplementary Information.\nshown in Fig. 11b. Could the authors clarify why Layer 5 was omitted? Additionally, the Te M₄-\nedge spectra appear largely similar across layers, with only minor variations that may fall\nwithin experimental noise. To substantiate the claim of \"distinct electronic environments,\" could\nthe authors provide quantitative analysis or clarify the significance of these spectral differences?\nResponse 5: We are sorry for the confusion. The ‘Layer 1’ in the original Supplementary Fig.\n11b refers to the first layer of MoTe starting from the interface and the ‘Layer 4’ the fourth.\nwhen we performed EELS experiments, with no corresponding relationship with numbers in\noriginal Supplementary Fig. 12b. Out of curiosity, we also scanned the Te M -edge spectrum of\n4\nm-Te over MoTe at that time (see Figure R6), which is the position 1 in original Supplementary\nMoTe was omitted.\npicture of electronic structures around atoms [Muller, D. Nat. Mater 2019, 8, 263–270]. Usually,\nthe energy shift of an EELS edge quantifies the change in valence states, usually when there is\na strong interaction at the interface [Y. Kim et al. J. Chem. Phys. 159, 5 (2023)]. In the case of\nm-Te/MoTe where the weak interaction does not lead to bonding, we observed no energy shift\n2\nbut changes in the edge shape, i.e., the curve slope of Layer 1 is unparallel to those of the layers\naway from the interface, quite different from the parallel scenario observed in [Y. Wang et al.\nNature 610, 7930 (2022)], which refers to identical electronic structures. Combined with\nanalysis of Raman, XPS, KPFM and DFT calculations, we attribute this minor disturbance of\n4\nresult in bonding, which manifests as no quantizable energy shift.\nBased on this comment, the mark numbers in EELS spectra have been adjusted for clear\ncomparison in revised Supplementary Information as Supplementary Fig. 17. To be clear, the\ncorresponding context has been modified in the revised manuscript as “In the EELS experiment,\nwe observed that the edge shape, i.e., the curve slope of interfacial MoTe Layer 1 in EELS\n2\nprofile (Supplementary Fig. 17) of the m-Te/MoTe scenario is unparallel to those of the layers\n2\naway from the interface, which refers to changed electronic structures, quite different from the\nparallel scenario in van der Waals Pt contact12. Thus, the p-type doping and defect compensation\neffects brought by m-Te create distinct electronic environments at the interface, making the\nfirst-layer Te in MoTe different from that of the inner parts. However, no obvious energy shift\n2\nwas observed, indicating that no new bonds were formed at the interface.”\nFigure R6. EELS showing the electronic structures of the Te atoms in MoTe near and\n2\naway from m-Te/MoTe interface.\npoints above would further support the authors’ claims and improve clarity.\nWe sincerely appreciate the reviewer’s positive assessment of our manuscript.\nComments: High performance p-type transistors are fundamentally crucial for atomically\nmonolithic thin TMDs-based next beyond-silicon electronics via the common CMOS technology.\nThis manuscript demonstrates a novel epitaxial growth strategy of metallic-phase tellurium (m-\nTe) on MoTe via evaporation as an efficient p-type contact. Through the comprehensive\n2\ninvestigation, monoclinic metallic P2 Te which typically requires high-pressure synthesis can\n1\nbe obtained through simple evaporation with the (021) plane aligned to the MoTe (100) plane.\nefficient p-type contact of MoTe transistors with near-barrier-free hole injection. Ultimately,\n2\nthe authors benchmark the bilayer MoTe transistor performance with the current reports. We\n2\nconsider the epitaxial growth of m-Te on MoTe (100) plane was systematically investigated\n2\nand such strategy offers another process selection to achieve good p-type contact quality of\nMoTe transistors. However, some crucial concerns of the actual feasibility of m-Te as a p-type\n2\ncontact for MoTe transistors should be addressed before its consideration for the publication\n2\nin Nature Communications as followed:\nComment 1.1: The authors have performed systematic investigation of vdW epitaxy of m-Te on\nMoTe , and the results are impressive and intriguing. In this section, the first concern is whether\n2\nchemical bonding occurs during the m-Te deposition on MoTe film, which requires more\n2\nexperimental verification such as XPS characterization. The vdW epitaxial growth is quite\nimportant for the contact quality and the following discussion.\nResponse 1.1: XPS is a powerful tool for analyzing valence state changes and bonding.\nHowever, it is difficult to determine whether the XPS signal of Te originates from Te atoms at\nthe interface, Te atoms in m-Te, or Te atoms in MoTe for the m-Te/MoTe interface. Hence,\n2 2\nXPS cannot provide effective feedback on whether Te atoms in m-Te and Te atoms in MoTe\n2\nform bonds. The only thing about bonding that can be determined through XPS results is that\nTe atoms in m-Te do not form bonds with Mo atoms in MoTe . As shown in Figure R7a and b,\n2\nboth Mo 3d and Te 3d core levels exhibit red shifts in the m-Te/MoTe heterostructure compared\n2\nto pristine MoTe . Such a parallel shift indicates a global change in the Fermi level rather than\n2\nlocal chemical bonding. This behavior is consistent with p-type doping of MoTe induced by\n2\nm-Te, while the absence of opposite shifts between Mo and Te core levels suggests that no new\nMo–Te bonding states formed at the interface.\nThe following evidences clearly indicate the van der Waals interaction between m-Te and\nMoTe .\nw\nTe is 0.206 nm, while the gap between m-Te and 2H MoTe was measured to be wider than\n2\n8\n0.33 nm in Fig. 2a, indicating a nonbonded interface between m-Te and 2H MoTe .\nbonding characteristics at the interface. Three types of interfacial bonds were considered: (1)\nTe-Te bonds at the interface (distances less than 3.8 Å), (2) Te–Te bonds of m-Te near the\ninterface, and (3) Mo-Te bonds in the uppermost layer of MoTe . The results are shown in\nvalues correspond to antibonding states and positive values represent bonding states. It can be\nseen that the −COHP values at the interface are much smaller than those in the bulk regions.\nThe −COHP curve of the interfacial Te–Te pairs shows only small oscillations around zero\nacross the entire energy range, quite different from fluctuating ones of Mo-Te pairs in MoTe\n2\nand Te-Te pairs in m-Te near the interface. The integration of −COHP with respect to energy\n(−ICOHP) quantitatively describes the bonding strength. As summarized in the table, the\n−ICOHP values up to the Fermi level for the interfacial Te–Te bonds, the Mo–Te bonds in 2H-\nMoTe , and the Te-Te bonds in m-Te are 0.15, 1.12, and 2.23 eV per bond, respectively. This\n2\nindicates the absence of appreciable covalent bonding between Te atoms across the interface,\nconsistent with a van der Waals-type contact.\nThe COHP results in Figure R7 have been added as Supplementary Fig. 18, and the\ninterfacial analysis has been included in the revised manuscript as “In addition, to further assess\nthe interfacial Te–Te interaction strength, −COHP (minus Crystal Orbital Hamilton Population)\ncurves and −ICOHP (integrated −COHP) were further computed. In Supplementary Fig. 18,\nthe −COHP curves show that the Te–Te interaction is much weaker than the Mo–Te interaction\nwithin 2H MoTe and the Te–Te interaction within m-Te, manifesting −COHP values hovering\n2\nclose to zero, with only small oscillations. This sharp contrast is then quantified by −ICOHP\nvalues, i.e., 0.15 eV per bond for interfacial Te–Te pairs, 2.23 eV per bond for MoTe Mo–Te\n2\npairs, and 1.12 eV for Te–Te pairs in m-Te”.\n2\nresult of p-doping of m-Te on 2H MoTe . c, d, −COHP curves (c) and −ICOHP (d) of Te-Te\n2\natoms at the interface, Mo-Te atoms in 2H MoTe , and Te-Te atoms in m-Te near the interface.\nsemiconducting trigonal phase under ambient conditions. We wonder except for the lattice\nmatch consideration, whether deposition conditions such as temperature would impact the m-\nTe phase formation. Whether the authors have verified how to control and optimize the M-Te\nphase formation? In other words, whether semiconducting Te film can be grown in MoTe\n2\nnanosheets and/or the substrate such as SiO /Si in other area?\n2\nimpacts the m-Te phase formation. To be specific, m-Te used as MoTe 's contacts is deposited\n2\nat room temperature, while semiconducting Te can be grown on MoTe at high temperature and\n2 2\nindicating the significance of lattice match and the inadequacy of SiO /Si as the substrate for\n2\n10\nm-Te growth due to the lack of lattice matching effect. We also deposited Te at 90 ℃ sample\nstage and found the same morphology of Te on SiO /Si and MoTe (Figure R8b). According to\n2 2\nthe XRD results (Figure R8c), it refers to trigonal Te (t-Te), i.e., the semiconducting Te. This\nmay be because heating increases the energy of Te adatoms and overcomes the energy barrier\ninduced by MoTe lattice.\nMoTe devices with no protective layers were annealed at 100 ℃, 200 ℃, 300 ℃ and 400 ℃\n2\nat 10-1 Pa for 45 min successively and tested to examine the stability of m-Te contacts through\nelectrical performances (Figure R9). The current of the devices after annealing at 100 ℃ and\n200 ℃ was higher than that of the initial devices. The performance of the devices after being\nannealed at 300 °C was worse than that of the initial devices; however, at this point, the current\nwas still quite high, and the device still worked normally. After being annealed at 400 ℃, the\nelectrodes became mesh-like and the devices were out of work.\nFurthermore, we have also optimized the formation of m-Te from the perspective of the\nevaporation rate. The optimal rate of thermal evaporation of Te on MoTe is 0.1 Å/s, as we\n2\nmentioned in the Method part.\nTo conclude, first of all, matching with the 2H MoTe lattice is a necessary condition for\n2\nthe existence of the metastable phase m-Te. Besides, deposition at relatively low temperature\n(room temperature) is another requirement to obtain m-Te.\nBased on this comment, the deposition details have been added to the Methods as a part\nof “The deposition of m-Te”.\na b c\nT\nR\ne\noo\no\nn\nt\nS\ne\ni\nm\nO\np\n2\ne\n/S\nra\ni\nture\nTeon SiO\n2\n/Si\nTeon 2H MoTe 2\nIntensity\n(a.u.) 2\n2\n(\nH\n(100)\n2\n2\n(\nH\n4) oTe\n2\n1\n(\nT\n00\n' M\n4)\noTet-Te\n(110)\nSi (111)\nMetallic Teon 2H MoTe 2 90 ℃ 90 ℃\n10 20 30\n2q (°)\nFigure R8. Te obtained by evaporation under various conditions. a, b The OM image of\nevaporated Te on SiO /Si and 2H MoTe at room temperature (a) and 90 ℃ (b). c, XRD results\n2 2\nof evaporated Te on thinned bulk 2H MoTe at 90 ℃; t-Te represents trigonal Te (P3 21).\n2 1\n2\nthermal annealing under different temperatures at 10-1 Pa. a-d, e-h and i-l correspond to\nthree devices, respectively.\nComment 1.3: Thirdly, how to verify the possible defects introduction such as the damage to\nthe MoTe channel during the deposition process, which is commonly unavoidable for\n2\ntraditional metal thermal deposition?\nResponse 1.3: The expanding full width at half maximum (FWHM) of Raman peaks is an\nindicator of surface damage. To verify the possible defect introduction by metal deposition, we\ndeposited 5 nm Te, 5 nm Pt and 5 nm Pd onto three MoTe samples separately and scanned\nWe noticed that for Pt/Pd-covered MoTe , a much broader w of A peak than that of the m-Te\n2 1g\ncovered sample can be observed. The FWHM of the latter has even decreased, which might be\nrelated to the defect compensation we mentioned in the manuscript. We thus consider that heavy\nmetals like Pt/Pd can cause more severe surface damage than m-Te on MoTe .\n2\nSupplementary Fig. 14c, d in the revised manuscript. The corresponding contexts have been\nmodified in the revised manuscript as “These heavy metals tend to generate intense thermal\nradiation during deposition12; their high momentum resulting from high atomic mass transfers\nsubstantial kinetic energy to the surface atoms of 2D semiconductors, exacerbating lattice\ndamage (Supplementary Fig. 1) and Fermi level pinning6.” in the introduction section, and\n“Note that no widening occurred of the A full width at half maximum (FWHM)\n1g\n(Supplementary Fig. 14c, d), distinct from Pt/Pd-contacted MoTe (Supplementary Fig. 1),\n2\nindicating negligible surface damage of m-Te contacted MoTe . The A peak even became\n2 1g\nnarrower after Te deposition. This might be related to the compensatory effect we mentioned\nabove.” on Page 10.\nFigure R10. Surface damage analysis by Raman spectra. Raman spectra of pristine MoTe\n2\n(a, c, e) and Te/Pt/Pd-covered ones (b, d, f). The corresponding optical microscope images are\nin the insets of a, c, e, respectively. Scale bar: 4 μm. Here, x represents the position of the A\nc 1g\npeaks, and w represents the FWHM.\nComment 1.4: Ultimately, the crucial concern in this section relies in the insufficient\ninformation about the m-Te film. Although the authors show the crystal structure and XRD\npattern of m-Te film, however, its vital material characteristics for suitable contact electrodes\nshould be further clarified. For example, the resistivity-temperature relationship should be\ngiven to verify its metallic nature except for the electronic structure theoretical calculation. The\n13\ncrucial factor of work function should be also verified by UPS, and the band alignment between\nm-Te and MoTe should be also verified by KPFM characterization;\nto carry out R-T (resistance-temperature) measurements, but found the device fabrication is\nvery difficult due to two main reasons: (1) 15 nm Te is prone to oxidation when exposed to air;\n(2) due to the weak interaction between the m-Te atomic layers, Te layer can easily disperse\nwhen spin coating PMMA on it. The details are provided below.\nWe conducted several different processing techniques. Primarily, to our best knowledge,\nm-Te can only be obtained on 2H MoTe at ambient conditions. Therefore, all the attempts\n2\nbegan with depositing 15 nm Te on MoTe . When we spin-coated PMMA on 15 nm Te to\n2\nprepare for EBL, we found that the Te film had fragmented, which may be attributed to the\nweak interaction between the Te atomic layers and MoTe , as well as between Te and SiO /Si\n2 2\nsubstrate.\nIn the second attempt, we directly coated PMMA on the exfoliated MoTe and exposed\n2\n‘window’ masks on it to deposit Te, just like usual EBL procedures for fabricating electrodes.\nHowever, m-Te on MoTe also detached from the surface of MoTe during lift-off, due to the\n2 2\nweaker interaction between m-Te and MoTe compared to the interaction between the Te and\n2\nedges surrounding the PMMA window mask.\nAs shown in Figure R11, we also tried transferring PMMA onto as-deposited Te on\nMoTe /substrates and etching out strips of 15 nm m-Te/MoTe . Based on this, we made two\n2 2\nattempts. (1) After the etching process, we did not remove the PMMA mask to prevent the Te\nfrom being removed by dissolving PMMA. We then performed EBL and prepared to evaporate\nAu electrodes. However, we found that due to the cross-linked PMMA, it was not possible to\nsuccessfully lift off. (2) There was also a small fraction of samples that fortunately did not\nexperience the situation where m-Te was completely removed from MoTe when they were\n2\nsoaked in acetone after being etched. As shown in Figure R12, we transferred the prepared Au\nelectrodes for testing but found that after going through too many steps and being exposed to\nthe air for too long, the m-Te had been oxidized, resulting in very low current or even un-work\ndevices.\nHowever, the following two evidence can demonstrate the metallic property of m-Te.\nTheoretically, we have determined the energy band structure of P2 Te (the structure has been\n1\nfully proven) through DFT calculations and reached the conclusion that it is metallic.\nExperimentally, during the subsequent UPS tests, we observed that the UPS of m-Te exhibited\nan evident Fermi level step, which is a characteristic of metallic materials.\nTo perform UPS characterization, 15 nm Te was evaporated onto the thinned bulk MoTe .\n2\nindicator of a metal. In contrast, the intensity of 2H MoTe spectrum near the Fermi edge fast\n2\napproaches the base line before the binding energy becomes zero (see Figure R15c), a sign of\na semiconductor. The secondary electron cutoff edge has been extracted from the low-kinetic-\nenergy (high-binding-energy) side in Figure R13b. For discussions on work function, please\nsee Response 2.1 below.\nm-Te was evaporated onto MoTe flakes exfoliated on heavily doped silicon substrate, and\n2\nthen KPFM characterization was conducted. The potential value in the KPFM image\ncorresponds to the electric potential difference between the tip and the sample. From Figure\nR14, we can calculate 𝜑 −𝜑 as\n𝑇𝑒 𝑀𝑜𝑇𝑒2\n(𝜑 −𝜑 )−(𝜑 −𝜑 )~45 𝑚𝑒𝑉\n𝑡𝑖𝑝 𝑀𝑜𝑇𝑒2 𝑡𝑖𝑝 𝑇𝑒\nIt can be seen that the electric potential of m-Te is higher, which facilitates the injection of holes\ninto MoTe . Note that KPFM characterization is sensitive to surface states; though the as-\n2\nevaporated fresh samples were used, the potential difference value can only be a reference.\nBased on this comment, the UPS results and band alignment in Figure R13 and Figure\nR15 have been added as Supplementary Fig. 11a-d, and KPFM results in Figure R14 as\nSupplementary Fig. 10 in the revised manuscript.\nFigure R11. Processing steps for m-Te devices based on exfoliated MoTe .\n2\ncorrespond to two different samples. c and g zoom in on d and h, respectively.\nFigure R13. Ultraviolet photoelectron spectrum (UPS) of m-Te/MoTe heterostructures. a,\nFigure R14. Kelvin probe force microscope characterizations of 30 nm m-Te deposited on\nMoTe . a, b, The OM image (a) and the KPFM image (b) of 30 nm m-Te on MoTe . Scale bars,\n2 2\n1 μm. c, d, Corresponding line profiles of height (c) and potential (d).\n2\nhole injection, however, such claim is lack of crucial evidences. Firstly, in line 205-211, the\nwork function of m-Te was determined as 4.65 eV, which is lower than the VBM of MoTe .\nthese values are easily underestimated by theoretical calculation, however, the VBM of MoTe\n2\nhas been well verified as ~4.8-5.0 eV experimentally. In this regard, the direct band alignment\nshould be supplemented.\nResponse 2.1: The band alignment diagram in the original Supplementary Materials and now\nshown in Figure R15a (Supplementary Fig. 11a) is derived from the band structures calculated\nby us using the PBE method, which can reveal the relative band relationship of the two materials.\nYet we agree with the reviewer that experimental results can provide more accurate values.\nSo, we also conducted UPS tests of 2H MoTe with the results shown in Figure R15b, c. With\n2\na Fermi edge of 16.92 eV and the secondary cutoff of 0.69 eV, the Fermi level of MoTe is 4.3\n2\neV, and the VBM is located at 0.69 eV below the Fermi level, which is 4.99 eV.\nAccording to the UPS results in Figure R13, the work function of the m-Te/MoTe\n2\nheterostructure is determined to be 21.22-16.65 = 4.57 eV. However, prior studies have shown\nthat increased surface roughness and step density can reduce the work functions of metals,\nwhich relates to the dipole moment and associated surface capacitance [J. Chem. Phys, 2005,\n122, 064708; Surface Science, 1977, 64, 52]. Here, we conducted the test on a thinned bulk of\nMoTe substrate, making it difficult to ensure ideal flatness. As a result, the measured work\n2\nfunction of m-Te is likely underestimated. In addition, m-Te cannot exist independently at\nambient conditions without a “MoTe substrate”; the obtained value in Figure R13 originates\n2\nfrom the m-Te/MoTe heterostructure, where the work function of m-Te and the Fermi level of\n2\nredistribution of the work function in the heterostructure compared to the individual\ncomponents (Figure R15a), suggesting that the value of 4.57 eV corresponds to the work\nfunction of the heterostructure as a whole (Figure R15d), rather than that of pure m-Te.\nBased on this comment, we have added Figure R13 and Figure R15 as Supplementary Fig.\n11a-d in the revised Supplementary Information, and modified the corresponding context in the\nrevised manuscript as “First-principles calculations and a clear Fermi step beyond the zero\nbinding energy in Ultraviolet Photoelectron Spectroscopy (UPS) confirm the metallic nature of\nP2 Te (Fig. 3a, the reciprocal primary cell is shown in Supplementary Fig. 7e; UPS results are\n1\nshown in Supplementary Fig. 11d), consistent with previous reports16, fulfilling the\nfundamental requirement for electrical contacts. In addition, the Kelvin probe force microscopy\n17\n(KPFM) results in Supplementary Fig. 10 indicate that the electric potential of m-Te is higher\nthan that of MoTe . The potential difference between m-Te/MoTe heterostructure and MoTe\n2 2 2\nis approximately 45 meV. UPS results in Supplementary Fig. 11a-c indicate the work function\nof m-Te/MoTe heterostructure is 4.57 eV, larger than the Fermi level of free-standing MoTe\n2 2\n(4.3 eV), confirming the positive charge transfer from m-Te to MoTe . The band offset of m-\n2 2\nSupplementary Fig. 11e” on Page 11.\nFigure R15. The band alignment of m-Te and MoTe . a, The band alignment calculated by\n2\nfirst-principles calculation. b, c, The UPS of MoTe , with secondary cutoff (b) and Fermi edge\n2\nprovided (c). d, The Fermi levels of free-standing 2H MoTe and m-Te/MoTe heterostructure\n2 2\nextracted from UPS results.\nComment 2.2: Secondly, In Fig. 3b, the MIGS should be given with the magnified PLDOS in\nthe bandgap. We doubted what is the special features of m-Te can indeed alleviate the MIGS,\nwhich enables the m-Te differing from other contact metal electrodes. The authors should\nclarify that.\nResponse 2.2: We zoomed in on the band gap on PLDOS (Figure R16) and found that the band\ngap of MoTe in contact with m-Te becomes narrower than that of the pristine one, and the\n2\nmetal-induced states lie within the band as a part of band edge. Specifically, the valence band\nedge of Te-contacted MoTe is composed mainly of Mo d 2 and Te p bends and shifts upwards\n2 z z\ncompared with pristine MoTe ; the conduction band edge of it is composed mainly of Te p\n2 z\nshifts downwards. They can be seen as the extension of the band edge, and combining our\nArrhenius experiment results, it will not cause Fermi pinning within the band gap. Besides,\nunlike traditional metal contacts toTMDs (Figure R17 and Figure R18 from Phys. Rev. X, 2014,\n4, 031005), there is no sharp state peak within the bandgap of MoTe in contact with m-Te;\n2\ninstead, the tiny MIGSs are delocalized within the whole bandgap.\nThe special features of m-Te MIGS-free contacts for MoTe involve: (1) The van der Waals\n2\ninterface with a gap over 3.3 Å reduces the spatial overlap between the orbitals of atoms in Te\n18\nand MoTe ; (2) Low thermal radiation during deposition causes less defects.\nthe revised manuscript. We have modified the corresponding contexts in the revised manuscript\nas “We zoomed in on DOS of the band gap in Supplementary Fig. 12 and found that the band\ngap of MoTe in contact with m-Te becomes narrower than that of the pristine one, and the\n2\nmetal-induced states lie within the band as an extension of band edge. Specifically, the valence\nband edge of Te-contacted MoTe composed mainly of Mo d 2 and Te p bends shifts upwards\n2 z z\ncompared with pristine MoTe , and the conduction band edge of it composed mainly of Te p\n2 z\nshifts downwards. As a result, the Fermi level (E ) of the heterojunction approaches the VBM\nF\nof MoTe , accompanied by electron depletion of it (Fig. 3c and Supplementary Fig. 11f)”.\n2\nof MoTe before (a) and after (c) in contact with m-Te. b, d, The magnified PDOS of a, c in the\n2\nbandgap, showing MIGS. Mo 𝑑 and Te 𝑝 orbitals of MoTe extend into the band gap after\n𝑧2 𝑧 2\nMoTe is in contact with m-Te. The E of the system approaches the valence band maximum of\nMoTe .\n2\n2 2 2 2\nMoS . e, Ti-MoS . f, Mo-MoS . Copyright © 2025 the Authors, licensed under a Creative\n2 2 2\nCommons Attribution 3.0 License.\nFigure R18. PDOS of top contacts to WSe : a, only WSe . b, Au-WSe . c, In-WSe . d, Pd-\n2 2 2 2\nWSe . e, Ti-WSe . f, W-WSe . Copyright © 2025 the Authors, licensed under a Creative\n2 2 2\nCommons Attribution 3.0 License.\nComment 2.3: Thirdly, for the electrical performance of the contacts, more crucial evidences\nshould be supplemented. For example, in Fig. 4b, although the m-Te/MoTe contact shows\n2\nlinear output characteristics in room temperature, the similar output characteristics at low\n20\ntemperature should be also clarified, since thermionic emission was suppressed at low\ntemperature. Meanwhile, the linear characteristics in Fig. 4b is reasonable in the range of 0V\nto -20V, because the device is always operated in “on” state in this gate range from Fig 4a. In\nthis regard, the gate voltage should be given from higher than 20V to -20V. Similarly and vitally,\nthe authors plotted an Arrhenius curve in Fig. 4d and claimed that positive slopes across\ndifferent gate voltages thus providing direct evidence for barrier-free charge injection. However,\nthe device is always operated in “on” state in this gate voltage range from -10V to -25V,\nimplying the bend bending of MoTe channel and barrier-free for hole injection. The authors\n2\nshould provide the extracted barrier height at different gate voltage, thus to obtain the barrier\nheight at flat-band. Another direct experimental evidence for the barrier-free hole injection lies\nin the increased on-state current with the decreased temperature, and the Ids-Vds curves as\nfunction of temperature should be also clarified;\nResponse 2.3: Let’s dive in and see the electrical characteristics of m-Te/MoTe transistors in\n2\ndetail. For low-temperature hole injection, the output characteristics of an m-Te contacted\nMoTe device with full-range gate voltages at temperatures from 100 K to 300 K are shown in\nthe device.\nAs for the questions about gate voltage range, the output characteristics under the positive\ngate voltages are not presented in the original manuscript because currents are too low in the\noff state, and even if full-range output curves were plotted together, curves under positive gates\nwould not be visible, as shown in Figure R20a. To demonstrate the output characteristics when\nV varies from 20 V to 0 V, they are shown solely here in Figure R20b. We can see good linear\ngs\noutputs can be maintained even at this range.\nBesides, curves with gate voltages ranging from 25 V to -10 V are added to the Arrhenius\nplots in Figure R21a and b. The device at positive gate voltages shows negative slopes in the\nArrhenius plot, which may originate from the energy difference between the Fermi level of the\nm-Te contacted MoTe and the valence band maximum of the depleted MoTe channel. Per the\n2 2\nreviewer’s request, the effective barrier height at different gate voltages were shown in Figure\nR21c, but only points at 1000/T between 4 and 6 in Figure R21a and b were used because the\nnonlinearity of Arrhenius curves (the nonlinearity can be attributed to the absence of a Schottky\nbarrier). According to the relationship between band offset and gate voltage as shown in Figure\nR21d, the transition point at positive-gate region in Figure R21c corresponds to the situation\nwhere, as the positive gate voltage increases, the VBM of MoTe is pulled to a position that is\n2\nparallel to the work function of m-Te (stage Ⅲ in Figure R21d), rather than the conventional\nflat band condition. As we can see, at this pseudo flat-band condition the barrier is only around\n12 meV, which might correspond to the energy required for holes to escape from the potential\n21\nwell at the contact interface.\nWhen extracting the current at different temperatures under the same effective gate voltage,\nit was found that the current increased continuously from 300 K to 160 K, but below 160 K,\nthe current began to decrease as the temperature dropped, as shown in Figure R22. This\nphenomenon can be attributed to different dominant scattering mechanisms. Below 160 K, the\ncurrent is limited by scattering from charged impurities, while electron–phonon scattering\nbecomes the dominant scattering mechanism at higher temperatures [Nat. Mater, 2013, 12, 815–\n820]. Hence, we believe that a decrease in temperature accompanied by an increase in current\nis a sufficient but not necessary condition for Ohmic contact, which can only happen when the\ninterface between 2D materials and dielectrics/substrates is ideal, as 2D materials are sensitive\nto interface scattering.\nBased on this comment, Figure R19 has been added as Supplementary Fig. 22a-k in the\nrevised manuscript. The corresponding content has been included as “Notably, the device\nexhibits primarily p-type transport behavior with excellent linearity at temperatures from 100\nK to 300 K (Supplementary Fig. 22a), confirming the formation of high-quality p-type ohmic\ncontacts”.\nOutput characteristics with full-range gate voltages have replaced the original ones in Fig.\n4b and those at positive voltages have been post separately in Supplementary Fig. 21, with a\nmodified texts “Notably, the device exhibits primarily p-type transport behavior with excellent\nlinearity at full-range gate voltages (Supplementary Fig. 21) and at temperatures from 100 K to\ncontacts” in revised manuscript.\n2\nFigure R20. Output characteristics of m-Te/MoTe devices with full-range gate voltages\n2\n(a) and positive gate voltages (b).\nwith gate voltages from 0 to -25 V (a) and 0 to 25 V (b). c, The extracted activation energy for\ncharge carrier injection as a function of V at V = -1 V. d, Corresponding band diagrams at\ngs ds\ndifferent gate voltages.\n1.9×10−4\n1.8×10−4\n)1.7×10−4\nA\n(\nnt\nr\ne 1.6×10−4\nr\nu\nC\n1.5×10−4\n1.4×10−4 p=1.1×1013 cm-2\n100 150 200 250 300\nTemperature (K)\nFigure R22. Temperature dependence of currents in a m-Te/MoTe device at hole density\n2\n(p) of 1.1 × 1013 cm−2.\nComment 3: Ultimately, the authors benchmark their devices with the state-of-the-art 2D p-\ntype FETs based on MoTe (blue) and undoped WSe (orange) (Figs. 4g, h). Firstly, to our best\n2 2\nknown, p-type WSe₂ transistors have already achieved R as low as 0.041 kΩ·μm (Science 388,\nc\n1183–1188 (2025)) and on-current up to 1.5 mA/μm (Nat. Electron. 5, 497–504 (2022)). The\ncomparison with WSe₂ should be more cautious. Meanwhile, recent investigations such as NO\nsurface doping (Nat. Commun. 16, 4160 (2025)), semimetal contacts (ACS Appl. Mater.\nInterfaces 17, 25518–25525 (2025); Nat. Commun. 14, 4747 (2023)) etc. have also shown\nexcellent p-type electronic performance. The authors should also benchmark these\ninvestigations;\nResponse 3: Based on this comment, the benchmark for the performance of p-type MoTe and\n2 2\ndevices is the best among the existing p-type MoTe devices, and it shows good compatibility\n2\nwith existing techniques.\nPer the reviewer’s request, the benchmark of current density and on/off ratio, contact\nresistance has been updated in Fig.4, Table 1 and Table 2.\nFigure R23. Updated benchmark of current density and on/off ratio, contact resistance of\np-type FETs based on MoTe FETs and undoped WSe FETs, with values reported in the\n2 2\nliterature using different methods. a, Benchmark of current density and on/off ratio of p-type\nMoTe FETs. b, Benchmark of current density and contact resistance of p-type FETs based on\n2 2\nof p-type MoTe FETs and WSe FETs, respectively. The symbols for solid and hollow,\n2 2\nrespectively, represent devices with 1-2 layers and three or more layers. All current densities\n25\nare collected at V of -1 V.\nds\nComment 4: Some more experimental details should be also supplemented. For example, for\ndevice fabrication, the exfoliated MoTe nanosheets were adopted as the device channel. In\n2\nsuch case, whether a large-scale m-Te film can be obtained? how to etch the unnecessary Te\nfilm selectively from the MoTe nanosheets and underlying substrate? How the etching process\n2\nimpact the quality of MoTe channel? Whether preferable growth of m-Te on the contact area\n2\nis feasible? In Fig. 4, bilayer MoTe₂ transistors were investigated. Further supporting evidence\nsuch as Raman, AFM step height, or optical contrast calibration should be provided to verify\nits bilayer thickness. Meanwhile, for the device electronic characteristics, the SS values should\nbe also given to further verify the contact quality and high-k dielectric/channel quality.\nResponse 4: Figure R24a shows the device fabrication process of m-Te/MoTe FETs. m-Te will\n2\nundergo oriented growth on the entire surface of MoTe , and the contact area is no exception.\n2\nprocesses shown in Figure R24b. For the devices used in TLM testing in our work, as well as\nthose to be fabricated from large-scale MoTe in the future, the deposition of Te can occur after\n2\nthe etching of MoTe , and there is no issue of etching away the Te film on MoTe . In this work,\n2 2\ndue to the need for characterization, we often need to exfoliate as much MoTe as possible onto\n2\nthe substrate before conducting subsequent Te deposition and characterization. The lack of\nlarge-area MoTe is indeed a hindrance to research. But as far as we know, many researchers\n2\nhave made significant breakthroughs in the growth of large-area MoTe [Science, 2021, 372,\n2\n195; Nat. Commun, 2023, 14, 4747]. In the future, we would try to collaborate with experienced\nresearchers who specialize in growing large-area MoTe to more efficiently promote the\n2\ndevelopment of P-type MoTe FETs.\n2\nactual experiment, we conducted a detailed analysis of MoTe thickness. As shown in Figure\nused the B 1/E 1 intensity ratio and the peak position of A as a reference for thickness\n2g 2g 1g\nidentification. In the subsequent experiments, the thickness was determined using Raman\nspectroscopy. By extracting the B 1/E 1 intensity ratios of MoTe with different thicknesses\n2g 2g 2\non Al O , we found that those with a ratio higher than 0.55 are monolayer, bilayer and three-\n2 3\nlayer MoTe , and those with A peak positions below 170.1 cm-1 are monolayer and bilayer\n2 1g\nones, which is similar to the trend previously reported regarding the relationship between the\nthickness of MoTe and the ratios of B 1/E 1 intensity on SiO substrates [ACS Nano, 2014, 8,\n2 2g 2g 2\n3895]. Note that monolayer MoTe is not stable enough for device fabrication, so the bilayer\n2 2g 2g\nratio higher than 0.55 and a peak position of A lower than 170.1 cm-1, so they are bilayer\n1g\nsamples.\n2 2\ndifferent layer numbers and corresponding thicknesses obtained via AFM. b and c represent the\nRaman spectra of monolayer and bilayer MoTe , respectively. e-g corresponds to MoTe with\n2 2\nthree layers and more. The B 1/E 1 ratios and A peak positions of MoTe with different\n2g 2g 1g 2\nthicknesses were extracted and displayed in h.\n𝑘 𝑇 𝑚𝑉\n𝐵\n𝑆𝑆 = 𝑙𝑛10 ≈ 60\n𝑚𝑖𝑛 𝑞 𝑑𝑒𝑐\nHowever, real devices exceed that because of series capacitances (depletion, interface\ntraps) and other non-idealities. The usual expression is\n𝑘 𝑇 𝐶 +𝐶\n𝐵 𝑖𝑡 𝑑\n𝑆𝑆 = ( 𝑙𝑛10)(1+ )\n𝑞 𝐶\n𝑜𝑥\nwhere C is the depletion-layer capacitance per unit area, which comes from charge in the\nd\nsemiconductor body that change when the surface potential is changed, and is negligible in 2D\nFETs. C is the interface-state capacitance per unit area. It’s worth noting that C comes from\nit it\nelectronic states at or near the interface between the semiconductor and dielectric that can trap\nor release carriers as the Fermi level moves and is not related to the contact interface.\nIn our work, we used 50-70 nm Al O deposited by ALD as the dielectric material. We\n2 3\nobtained the values of SS based on\n𝑑(𝑙𝑜𝑔 𝐼 )\n𝑆𝑆 = ( 10 𝐷 )−1\n𝑑𝑉\n𝑔𝑠\nAnd the values of SS extracted from the transfer characteristic curves range from 103 to 3\n×103 mV/decades. According to the CV test, the C (gate oxide capacitance per unit area)\nox\nvalues of these dielectrics ranged from 7×10-8 F/cm2 to 1.4×10-7 F/cm2.\nThe relationship between capacitance and trap density is\n𝐶 = 𝑞𝐷\n𝑖𝑡 𝑖𝑡\nAccording to the relationship between capacitance and trap density, 𝐶 = 𝑞𝐷 , the\n𝑖𝑡 𝑖𝑡\ninterfacial defect states are of the order of 1013 cm-2 eV-1. In order to further enhance the\nperformance of the p-type 2D FETs, high-quality dielectric and interface are needed.\nBased on this comment, the thickness analysis has been added as Supplementary Fig. 19\nand Supplementary Fig. 20 in the revised manuscript. Figure R24 has been added as\nSupplementary Fig. 27, with the modified contexts “Compared to metal transfer or CVD-grown\nepitaxial approaches42,47, our direct thermal evaporation of Te offers superior compatibility with\nexisting silicon technologies since the transfer process is omitted and there is no need to\nconsider the etching issue after m-Te growth. As shown in Supplementary Fig. 27, the m-Te\n29\ncontact strategy also has the potential to be extended to the fabrication of devices on large-scale\nMoTe , facilitating subsequent integration.” in the revised manuscript.\n2\nThis study by Zhu et al. aims to address the p-type contact challenge in 2D semiconductors by\nintroducing metallic tellurium (m-Te) as a novel contact material. Using van der Waals (vdW)\nepitaxy, the authors grew monoclinic metallic Te (m-Te) on 2H-MoTe , achieving close lattice\n2\nmatching and stable bonding without high-pressure conditions. Since MoTe can be tuned to be\n2\np-type and shares structural compatibility with Te, the deposited Te atoms align to form a\nmetallic layer with ideal band alignment and minimal MIGS, enabling low-resistance, high-\nquality p-type contacts. This Reviewer believes that the study offers a new direction for\naddressing the p-type contact challenge in 2D electronic devices, despite some practical\nconstraints. However, for the publication of this study, it is considered necessary to address the\nfollowing points and overcome the associated limitations.\nComment 1: The key to achieve vdW epitaxy seems to be matching the m-Te (021) planes with\nthe 2H-MoTe (-1100) planes, with aligned unit cell dimensions. How universal is this growth\n2\napproach via evaporation, and does it have a limited growth window?\nResponse 1: Lattice matching is the principle for obtaining m-Te on MoTe , and temperature\n2\nimpacts the m-Te phase formation. To be specific, m-Te is deposited at room temperature, while\nsemiconducting Te will form at high temperature.\nAs shown in Figure R27, Te on MoTe and Te on SiO /Si show distinct morphology,\n2 2\nindicating the significance of lattice match and the inadequacy of SiO /Si as the substrate for\n2\nm-Te growth due to the lack of lattice matching effect. We also deposited Te at 90 ℃ sample\nstage and found the same morphology of Te on SiO /Si and MoTe (Figure R27). According to\n2 2\nthe XRD results (Figure R27c), it refers to trigonal Te (t-Te), i.e., the semiconducting Te. This\nmay be because heating increases the energy of Te adatoms and overcomes the energy barrier\ninduced by MoTe lattice.\nHere, three MoTe devices with no protective layers were annealed at 100 ℃, 200 ℃, 300 ℃\n2\nand 400 ℃ at 10-1 Pa for 45 min successively and tested to examine the stability of m-Te contacts through\nelectrical performances (Figure R30). The current of the devices after annealing at 100 ℃ and\n200 ℃ was higher than that of the initial devices. The performance of the devices after being\nannealed at 300 °C was worse than that of the initial devices; however, at this point, the current\nwas still quite high, and the device was able to function normally. After being annealed at\n400 ℃, the electrodes became mesh-like and were no longer able to connect properly; and the\ndevice was open-circuited in this case.\nFurthermore, we have also optimized the formation of m-Te from the perspective of the\n31\nevaporation rate. The optimal rate of thermal evaporation of Te on MoTe is 0.1 Å/s, as we\n2\nmentioned in the Method part.\nTo conclude, first of all, matching with the 2H MoTe lattice is a necessary condition for\n2\nthe existence of the metastable phase m-Te. Besides, deposition at relatively low temperature\n(room temperature) is another requirement to obtain m-Te.\nBased on this comment, the deposition details have been added to the Methods as a part\nof “The deposition of m-Te”.\na b c\nT\nR\ne\noo\no\nn\nt\nS\ne\ni\nm\nO\np\n2\ne\n/S\nra\ni\nture\nTeon SiO\n2\n/Si\nTeon 2H MoTe 2\nIntensity\n(a.u.) 2\n2\n(\nH\n(100)\n2\n2\n(\nH\n4) oTe\n2\n1\n(\nT\n00\n' M\n4)\noTet-Te\n(110)\nSi (111)\nMetallic Teon 2H MoTe 2 90 ℃ 90 ℃\n10 20 30\n2q (°)\nFigure R27. Te obtained by evaporation under various conditions. a, b The OM image of\nevaporated Te on SiO /Si and 2H MoTe at room temperature (a) and 90 ℃ (b). c, XRD results\n2 2\nof evaporated Te on thinned bulk 2H MoTe at 90 ℃; t-Te represents trigonal Te (P3 21).\n2 1\nComment 2: Could it be that the desired vdW epitaxy occurred only under specific evaporation\nconditions on the bilayer MoTe film? To verify this, this Reviewer suggest examining whether\n2\nthe m-Te layer exhibits vdW epitaxy on MoTe samples of different thicknesses, which can be\n2\nreadily obtained via mechanical exfoliation.\nResponse 2: m-Te can be obtained on MoTe of any thickness. As shown in Figure R28, the\n2\nmorphology of Te on MoTe of different thicknesses shows three main orientations, which is\n2\nthe same as the m-Te morphology that we confirmed its structure by TEM and XRD before.\nFurthermore, the Te samples used for XRD analysis in Fig. 2d were obtained by\nevaporating Te on a substrate full of exfoliated MoTe (covering almost the entire 0.5 cm × 0.5\n2\ncm substrate surface). These exfoliated samples included MoTe of various thicknesses, and the\nSupplementary Information, with modified contexts as “The Te film shows a textured\nmorphology with three dominant orientations on MoTe with different thicknesses\n2\n(Supplementary Fig. 5), which is distinct from the randomly distributed spherical clusters on\nsilicon dioxide (SiO ), indicating the possibility of van der Waals oriented growth19,20”.\n2\n2\ndiscussion of how they might differ for monolayer samples. Since contact properties in 2D\nmaterials often degrade as the layer number decreases, verifying the method on monolayer\nMoTe would help clarify its limitations and applicability. If necessary, contact resistance\n2\nmeasurements could be performed, and the use of a gate metal or auxiliary layers could be\nconsidered.\nResponse 3: Actually, we had tried to fabricate devices based on monolayer MoTe . However,\n2\nmonolayer MoTe is extremely unstable and can gradually disappear due to the exposure to air\n2\nduring the processing. We tried to exfoliate the samples in glovebox, but the device didn’t work\nbecause the liftoff process must be done at atmosphere, let alone the TLM devices that a series\nof processes are involved. That’s why bilayer MoTe was mainly studied. The process of adding\n2\na protective layer actually prolongs the time that MoTe exposing to the air or introduces more\n2\nunstable sources, like water during the deposition of dielectrics. Even for few-layer MoTe as\n2,\nshown in Figure R29, the performance degarded after capping an additional layer of Al O .\n2 3\nIn the light of this comment, Figure R29 has been added as Supplementary Fig. 29 in the\nrevised Supplementary Information. We have added the discussion about auxiliary layers as\n33\n“Note that the process of adding a protective layer actually prolongs the time that MoTe\n2\nexposing to the air or introduces more unstable sources, like water during the deposition of\ndielectrics. As shown in Supplementary Fig. 29, we observed the performance degradation even\nin multilayer devices after capping an additional layer of Al O . Therefore, in this work, the m-\n2 3\nTe/MoTe FETs did not employ any protective capping layers.” in the Methods.\n2\ntwo different few-layer m-Te/MoTe FETs, respectively.\nverification is needed under thermal and current stress. Since tellurium can resublime at\nelevated temperatures or interdiffuse with metals, it is worthwhile to assess whether m-Te\ncontacts remain stable after thermal annealing or prolonged operation, and explore reliability\nenhancements through protective layers if necessary.\nResponse 4: Thank you for your insightful questions. The following experimental results show\nthat the device can still function after being annealed at 300 ℃. And after long-term operation,\nm-Te/MoTe devices can maintain their performance.\n2\nand 400 ℃ at 10-1 Pa for 45 min successively and tested to examine the stability of m-Te contacts through\nelectrical performances (Figure R30). The current of the devices after\nannealing at 100 ℃ and 200 ℃ was higher than that of the initial devices. The performance of\nthe devices after being annealed at 300 °C was worse than that of the initial devices; however,\nat this point, the current was still quite high, and the device still worked normally. After being\nannealed at 400 ℃, the electrodes became mesh-like and the devices were out of work.\nTo investigate the stability of the m-Te/Au electrodes during annealing when a protective\nlayer is present, we transferred 7-nm Al O onto the as-fabricated m-Te/MoTe (Figure R31)\n2 3 2\nand then repeated the same annealing process. Unfortunately, either Al O was not a suitable\n2 3\nprotective layer for p-type FETs, or the extra processes and exposure to the air could make\n2 2 3 2\ncompared to the initial ones, as shown in Figure R32. Moreover, whether there is a protective\nlayer or not, the annealing temperature has the same effect on the devices. Specifically, at\nannealing temperatures from 100 ℃ to 200 ℃, the performance of the devices was continuously\nimproving. Around 300 ℃, the performance began to decline. After being annealed at 400 ℃,\nthe devices completely failed.\nFurthermore, we applied a constant bias of 0.5 V to an m-Te/MoTe device at a gate voltage\n2\nof -20 V (Figure R33a). After 1000 s of such voltage application, re-testing revealed that the\nm-Te/MoTe device was able to maintain its initial performance (Figure R33b, c). The slight\n2\ncurrent variations are caused by the threshold voltage changes resulting from charge traps by\nthe defect states in Al O during continuous gate voltage applying. The output characteristics\n2 3\nremain linear after 1000 s of voltage application (Figure R33c), indicating that prolonged\noperation has a weak effect on the m-Te contact.\nThank you for your questions, so that a more comprehensive understanding of the\nproperties of m-Te contacts can now be provided for readers and ourselves. Based on these\nresults, we have added Figure R30 and Figure R33 as Supplementary Fig. 23 and\nSupplementary Fig. 24 in the revised Supplementary Information. Besides, we have added the\nfollowing description in the revised manuscript as “… and the m-Te contacts remain stable after\n300 ℃ annealing and 103 s prolonged operation as shown in Supplementary Fig. 23 and\nSupplementary Fig. 24”.\n2\nthermal annealing under different temperatures at 10-1 Pa. a-d, e-h and i-l correspond to\nthree devices, respectively.\nFigure R31. The process of adding a protective layer (7 nm Al O ) to m-Te/MoTe devices.\n2 3 2\n2 3\ncorrespond to two devices respectively.\n2 2\nwas applied a constant bias voltage of 0.5 V under a gate voltage of -20 V for 103 s. b and c\ncompare the transfer and output characteristics of the FET before and after prolonged operation,\nrespectively.\nComment 5: The authors demonstrated excellent p-type FET performance at a channel length\nof ~130 nm. However, most studies report device performance at micrometer-scale channel\nlengths achievable via photolithography. For a clearer comparison, it would be helpful if the\nauthors could also provide such data for their samples, if available.\nResponse 5: The current density of m-Te/MoTe FETs with long-channel lengths is shown in\ndensity of MoTe using other schemes, as well as the data for long-channel WSe FETs. Note\n2 2\nthat thicker two-dimensional materials possess better contact property and scattering immunity,\nand a consequent higher current.\nds\n1)\n-m30\nm\nA\nm\ny\n( This Work\nsit20\nn\ne\nd\nnt\ne\nurr10 Ti\nC\n1T' MoTe\n2\nhBN contact gate\nlateral 1T' MoTe\n0 2\n1 2 3 4\nChannel length (mm)\n2\nrepresent the data of m-Te/MoTe FETs. The blue symbols correspond to MoTe FETs reported\n2 2\nusing other schemes. The orange symbols represent WSe FETs. The solid and hollow\n2\nindicators correspond to FETs of monolayer/bilayer and of multilayer, respectively.\nWe thank all the reviewers for their valuable comments. They have helped us to prepare a better\nmanuscript. Point-by-point response to reviewers’ comments follows.\nResponse to Reviewer #1:\nComments: The authors have replied to my comments satisfactorily, besides a minor typo:\nIn supplementary Fig. 8, above the tables in panels d and g, the crystal system is still mislabeled.\nBoth are shown as “Triclinic.”\nResponse: The crystal system mentioned in the tables in Supplementary Fig. 8 refers to the\nentire triclinic supercell of the heterostructures, rather than tellurium solely. To avoid any\nambiguity, we have added “heterostructure” in the caption.\nResponse to Reviewer #2:\nComments: The authors have carefully addressed our concerns. Before publication in Nature\nCommunications, the minor revision was suggested to be made:\nWe appreciate the authors' detailed feedback in Response 2.3 regarding the low-temperature\nmeasurements and Arrhenius plots. However, the response is still quite confusing as below:\nComment 1: The author’s statement that \"the nonlinearity of Arrhenius curves... can be\nattributed to the absence of a Schottky barrier\" is quite confusing. Generally, the nonlinearity\nin Arrhenius plots particularly at high temperature (lower part of 1000/T axis) was interpreted\nby the temperature dependence of carrier mobility, which dominates over the thermionic\nemission current (Nature volume 593, pages211–217 (2021)). Such interpretation corresponds\nto the author’s observation in FigS13a that the device's on-current increases from 300 K to 160\nK. Selecting only three data points (1000/T between 4 and 6) to extract the effective barrier\nheight is statistically insufficient. The possible deviation from the actual barrier height was\nsuggested to be discussed.\nResponse 1: Thank you for your insightful reminder. First of all, regarding nonlinearity, we\ncan zoom in on the Arrhenius plots from Figure R1a and b, taking -5 V~0 V as an example. As\nshown in Figure R1c, the Arrhenius curves can be divided into three parts. In stage Ⅰ, as the\nreviewer pointed out, the variation of current with temperature is mainly determined by the\nchange of hole mobility with temperature at high temperatures [Nature 2021, 593, 211–217];\nwhile the trends of Arrhenius points in stage Ⅱ and stage Ⅲ are apparently different. The\ndistinction between Ⅱ and Ⅲ can be understood from two aspects: (1) As the temperature\ndecreases, the dominant scattering mechanism gradually shifts from electron-phonon scattering\nto charged impurities scattering [Nat. Mater 2013, 12, 815–820]. The carrier mobility first\nincreases (Ⅰ to Ⅱ) and then decreases (Ⅱ to Ⅲ). From stage Ⅱ to Ⅲ, the carrier mobility will\ngradually decrease, but the steepness can be more gradual than the influence of temperature on\nthe mobility at high temperatures. (2) From stage Ⅱ to Ⅲ, as the temperature continues to\ndecrease, the holes gradually lack sufficient thermal energy (k T), and tunneling may contribute\nB\na lot to the total hole injection mechanism.\nConsidering that at high temperatures mobility is significantly affected by temperature, and the\nunavoidable contribution of tunneling at low temperatures (low k T for carriers), we chose stage\nB\nⅡ (ranging from 4 to 6, corresponding to 240 K, 220 K, 200 K and 180 K) to extract the barrier.\nGenerally, the barriers are extracted from the Arrhenius plots based on the relationship between\ncurrent and temperature. And the total measured current is set by the series combination of\ncontact-limited injection and channel resistance, which are altered by temperature-dependent\nmobility, especially the latter one, considering that the channel length of the device used to\nanalyze the barrier is 400 nm. The deviation between the extracted barrier and the actual barrier\nmainly stems from the competitive relationship between the mechanisms of current variation\nwith temperature: (1) At high temperatures, the mobility decreases as the temperature rises,\nthereby reducing the current level. This causes the front curve of the Arrhenius plots to bend\ndownward, which may result in the extracted barrier being lower than the actual value. (2) At\nlow temperatures, the mobility decreases as the temperature decreases, which also causes the\ntail part of the Arrhenius plots to bend downward, which may result in the extracted barrier\nbeing higher than the actual value.\nIn view of the above, analysis of the Arrhenius plots has been included as Supplementary Fig.\n26 in the Supplementary Information. And the following discussion has been added in the\nMethods section: “It is worth noting that the total measured current is set by the series\ncombination of contact-limited injection and channel resistance, which are altered by\ntemperature-dependent scattering mechanisms50, especially the latter one considering that the\nchannel length of the device used to analyze barrier is 400 nm, manifesting as temperature-\ndependent current in Supplementary Fig. 26a. This causes the Arrhenius point to exhibit\nnonlinearity in Supplementary Fig. 26b, c.”\nFigure R1. Temperature dependence of currents and Arrhenius plots. a, b, c, Arrhenius\nplots with gate voltages from 0 to -25 V (a), 0 to 25 V (b) and 0 to -5 V (c). V = -1 V. d,\nds\ntemperature dependence of currents and Arrhenius plots in a m-Te/MoTe device at hole density\n2\n(p) of 1.1 × 1013 cm−2. Below 160 K, the current is limited by scattering from charged impurities,\nwhile electron–phonon scattering becomes the dominant scattering mechanism at higher\ntemperatures.\nComment 2: The author’s statement in figure R21d that “as the positive gate voltage increases,\nthe VBM of MoTe is pulled to a position that is parallel to the work function of m-Te\" is\n2\nphysically confusing. We understand that the gate voltage modulates the channel surface\npotential thus cause band bending. In this regard, the band diagram was suggested to be revised.\nResponse 2: We are sorry for the unclear description. The statement about Figure R2 of\n“parallel VBM and work function” should be modified as “The VBM of MoTe channel can be\n2\naligned with respect to the work function of m-Te when the positive gate modulation reaches a\ncertain point”.\nA modified discussion of the band diagrams (Supplementary Fig. 27) has been added in\nSchottky-barrier-extraction part of Methods section as “To make the physical picture clearer,\nwe analyzed the gate-modulated band diagram in Supplementary Fig. 27. After m-Te and\nMoTe contact, the band offset at the interface is fixed. Since the work function of m-Te is\n2\nhigher than the VBM of MoTe , as gate voltages change, the channel part of MoTe can be\n2 2\naligned with respect to the m-Te when the positive gate modulation reaches a certain point,\nrather than the conventional flat band condition. The “barrier” energy of this pseudo flat-band\ncondition might correspond to the energy required for holes to escape from the potential well\nat the contact interface.”\nFigure R2. Band diagrams at different gate voltages.\nResponse to Reviewer #3:\nThe authors have provided logical answers to the given questions through additional\nexperiments. This Reviewer believes that the study offers a new direction for addressing the p-\ntype contact challenge in 2D electronic devices, despite some practical constraints. In principle,\nthis Reviewer agrees with the publication of the revised manuscript.\nResponse: Thank the reviewer for joining us in exploring this work in a broader and more in-\ndepth manner."}]

Decision letter