1.1eV
23eV

3.4eV
3×106SiSi

Si

3×105

10

101/10X

Exp.

Calc.

Guo et al., Electronic structure of GaInN semiconductors investigated by x-ray absorption
spectroscopy, Applied Physics Letters, 98, 181901-1-3, 2011.

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October 21, 2020
11:00 11:30

Qixin Guo
Synchrotron Light Application Center, Saga University
Department of Electrical and Electronic Engineering
Saga University, Saga 840-8502, Japan

https://www.hitachi-hightech.com/jp/products/device/semiconductor/properties.html

Si, GaAs, GaP: Relatively narrow bandgap of less than 2.3 eV

Si, Ge, C (Diamond)
4H-SiC, ZnO, GaN: Wide bandgap of about 3.4 eV
Ga2O3 , Diamond, AlN, MgO, : Ultrawide bandgap of wider than 3.4 eV

III-V GaAs, InAs, GaInAs, AlGaAs, AlInAs
GaP, InP, GaInP, AlGaInP. GaInAsP
GaN, AlN, InN, BN, GaInN, AlGaN, AlInN
II-VI

ZnSe, ZnTe

IV IV SiC
: ZnO, Ga2O3

Thermal stability of InN
Guo et al., J. Appl. Phys. 73, 7969 (1993)

Epitaxial growth of InN by Microwave excited MOVPE
Guo et al., J. Appl. Phys. 75, 4927, (1994)
Guo et al., Appl. Phys. Lett. 66, 715, (1995)- 10 -

Epitaxial growth of AlInN by Microwave excited MOVPE

Growth of InN on glass substrate

Guo et al. J. Crystal Growth 146, 462 (1995)
Guo et al. Jpn. J. Appl. Phys. 34, 4653 (1995)

Guo et al., J. Crystal Growth 189/190, 466 (1998).
Guo et al., Thin Solid Films 343-344, 524 (1999).

Difficult to grow AlInN in theentire compositional regions

Growth of GaN by reactive sputtering

Growth of InGaN by reactive sputtering

Guo et al., Journal of Crystal Growth, 237/239, 1079 (2002).
Guo et al., Journal of Vacuum Science and Technology (A), 22, 1290 (2004).

Guo et al., Japanese Journal of Applied Physics 49, 081203 (2010).

-GaN (1013)(0002) GaN

750
0100200(deg)

300

700

650-400 -2000 200(arcmin)

400

Growth of AlN by reactive sputtering

Growth of AlInN by reactive sputtering (1)Guo et al., Journal of Crystal Growth, 257, 123 (2003).
Guo et al., Thin Solid Films, 483, 16 (2005).
Guo et al., Vacuum, 80, 716 (2006).

Guo et al., Journal of Crystal Growth, 300, 151 (2007).

- 11 -

Guo et al., Solid State Communications, 83, 721 (1992).

SOR-RINGUVSOR

Guo et al., Physical Review B 55, R15987 (1997).

Guo et al., Physical Review B 64, 113105 (2001).

Guo et al., Physical Review B 58, 15304 (1998).

Guo et al., Applied Physics Letters 86, 111911 (2005).

- 12 -

Guo et al., Applied Physics Letters 98, 181901 (2011).

Growth of Ga2O3
10 15 20 25 30 35 40 45 50 55 60 65 70

200 C

300 C

Highly (-Ga2O3 can beobtained at substrate temperature of 500oC.
400 C

500 C

600 C
10 15 20 25 30 35 40 45 50 55 60 65 70

2degrees

Zhang et al. and Q.X. Guo*, J. Cryst. Growth, 387 (2014) 96.

Si doped Ga2O3

Growth of (Ga1-xInx)2O3

The indium content (x) in the films increases almost linearly with the increase ofindium content (xtar) in the targets
Zhang et al. and Q.X. Guo*,
Applied Physics Letters, 109 (2016) 102105

Zhang et al. and Q.X. Guo*, Solid State Comm. 186 (2014) 28.

Growth of (Ga1-xAlx)2O3

Growth of (Ga1-xAlx)2O3

Zhang et al. and Q.X. Guo*, Appl. Phys. Letts. 105 (2014) 162107

Zhang et al. and Q.X. Guo*, Appl. Phys. Letts. 105 (2014) 162107- 13 -LED

Li et al. and Q.X. Guo*, Appl. Phys. Letts. 107 (2015) 022109.

HAXPES in BL46XU of SPring-8Eg (eV)The valence band spectra of PES at 8 keVpresented the main contribution from Ga
4sp, which are well represented byphotoionization cross section weighted
partial density of states.
The experimental data complemented withthe theoretical study yield a realistic
picture of the electronic structure for
Ga2O3

nm =1240eV)

https://en.wikipedia.org/wiki/LightLED
Guo et al., Jpn. J. Appl. Phys. 33, 2453 (1994).
Ga2O3TrappingcenterEr
4S

3/2, 550 nm
4I

15/2

LED

Chen et al. and Guo*, Superlattice Microstructures 90 (2016) 207

Chen et al. and Guo*, Superlattice Microstructures 90 (2016) 207

(b)

(c)

(d)

(e)

Er doped Ga2O3 films were deposited on sapphire substrates for the first time.
Intense pure green emissions at 550 nm are clearly observed for the Er doped films.

- 14 -No peak shift at 550 nm is found with temperatures ranging from 77 to 450 K.
The intensity of the Er doped Ga2O3 films has a smaller variation with temperaturecompared to GaN.

Nishihagi et al. and Guo*, Materials Research Bulletin 94, 170 (2017).

Bright green emission (548 nm) can be observed by naked eye from Ga2O3:Er/Si
light-emitting devices (LEDs).
The driven voltage of this LEDs is 6.2V which is lower than that of ZnO:Er/Si orGaN:Er/Si devices.
Ga2O3 contain more defect-related level which will enhance the effects ofrecombination, resulting in the improvement of the energy transfer to Er ions.
Chen et al. and Guo*, Appl. Phys. Lett. 109 (2016) 022107

SummaryGuo et al. , Thin Solid Films 639, 123 (2017).

Wide bandgap semiconductors are promising for
applications in solid state lighting and nextgeneration power electronic devices.
Characterization by using synchrotron light ispowerful for revealing structural, electronic, andoptical properties of advanced thin films.

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