bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorescent and Magnetic Resonance Imaging by Rare Earth Doped Nanoparticles with Garnet Structure
Authors: Asakura Ryo , Sakane Hiroshi , Noda Kunihiro , Isobe Tetsuhiko , Morita Masahito , Inubushi Toshiro 
Published: April 2011

ABSTRACTYb3+ doped Y3Al5O12 (YAG:Yb3+) nanoparticles are prepared from yttrium acetate tetrahydrate, ytterbium acetate tetrahydrate and aluminum isopropoxide in 1,4-butanediol by autoclave treatment at 300 °C for 2 h. Moreover, Gd-YAG:Yb3+ nanoparticles are prepared from the mixture of YAG:Yb3+ colloidal solution and gadolinium acetate tetrahydrate by the same autoclave treatment as YAG:Yb3+. Properties of structure, near infrared photoluminescence and magnetic resonance contrast enhancement are characterized for as-prepared and calcined YAG:Yb3+ and Gd-YAG:Yb3+ nanoparticles.
Stable, Hydrophilic Nitrilotriacetic Acid-Capped Gold Monolayer Protected Clusters
Authors: Sosibo Ndabenhle M. , Tshikhudo Robert T. , Revaprasadu Neerish 
Published: April 2011

ABSTRACTA one step synthesis and functionalization of robust, hydrophilic monolayer protected clusters of gold (Au-MPCs) containing a nitrilotriacetic acid (NTA) is described. The 14 nm Au-MPCs were prepared by the attachment of two bifunctional thioalkylated-poly(ethylene glycol) ligands on the nanoparticles, one containing a nitrilotriacetic acid (NTA) terminal group, while the second hydroxyl (OH) terminated ligand was used as a co-stabilizer to promote the stability of the MPCs. The resulting PEGylated NTA functionalized Au MPCs, which are characterized by TEM, UV-vis and agarose gel electrophoresis are attractive probes for many target species e.g. hexahistidine-tagged proteins. Importantly, the NTA functionality on MPCs ligand shell can be varied.
Synthesis of Cu-In-S Fluorescent Nanocrystals
Authors: Watanabe Kosuke , Uehara Masato , Nakamura Hiroyuki , Maeda Hideaki 
Published: April 2011

ABSTRACTCuInS2 (CIS) fluorescent nanocrystals (NCs) were obtained by heating organic metal complex. The photoluminescence (PL) originated from the donor-acceptor, and the quantum yield (QY) was achieved at 6%. Furthermore, we doped some metal ions (Zn2+, Cd2+ or Ag+) by the post heat-treatment in the organic coordinating solvent in order to tune the band gap of NCs. By this post treatment, the alteration of NCs structure was suggested, such as changing into an alloying and composite structure. In Zn-doping, the PL wavelength was widely tuned from 535 to 650 nm by alloying between CIS and ZnS. Moreover, PL intensity was increased with these structure alterations. In particular, the materials doped with Zn or Cd achieved respective QY of 25% and 40%.
Fabrication and Characterization of Individually Controlled Multi-Pixel Carbon Nanotube Cathode Array Chip for Micro-RT Application for Cancer Research
Authors: Wang Sigen , Liu Zhijun , An Lei , Zhou Otto , Chang Sha 
Published: April 2011

ABSTRACTCarbon nanotubes (CNTs) have attracted considerable attention as future field emission electron sources for a variety of applications due to their high aspect ratio and robust structure. One application is multi-pixel beam array x-ray micro-RT (radiotherapy) for small animal irradiation. The x-ray pixel beam array is produced by a CNT pixel cathode array. One challenge in the micro-RT fabrication is how to fabricate individually addressable multi-pixel CNT cathode array on wafer with high pixel beam packing density and high emission current. We report here the development of a new CNT field emission multi-pixel cathode array chip, a vital component of the multi-pixel beam x-ray micro-RT system under development. The CNT field emission cathode array has up to 25 (5 × 5) individually addressable cathode pixels, each is 1 mm in diameter and with center-to-center distance of 2 mm. The fabrication is a two-step process: first a Cr/Cu electrical contact was fabricated on Si substrates with a 5 μm SiO2 dielectric layer using photolithography; and second the CNTs were selectively deposited on 1 mm-diameter predefined Cr/Cu contact dots by using a combined photolithography/electrophotoresis technique. The electron pixel beams produced from the multi-pixel arrays are uniform and individually controllable and can be used for micro-RT application.
Electronic Transport in Co-deposited Hydrogenated Amorphous/Nanocrystalline Thin Films
Authors: Adjallah Y. , Blackwell C. , Anderson C. , Kortshagen U. , Kakalios J. 
Published: April 2011

ABSTRACTMixed-phase hydrogenated amorphous silicon thin films containing nanocrystalline silicon inclusions have been synthesized in a dual chamber co-deposition system. A PECVD deposition system produces small crystalline silicon particles (3-5 nm diameter) in a flow-through reactor, and injects these particles into a separate capacitively-coupled plasma chamber in which hydrogenated amorphous silicon is deposited. Raman spectroscopy is used to determine the volume fraction of nanocrystals in the mixed phase thin films, while infra-red spectroscopy characterizes the hydrogen bonding structure as a function of nanocrystalline concentration. At a moderate concentration of 5 nm silicon crystallites, the dark conductivity and photoconductivity are consistently found to be higher than in mixed phase films with either lower or higher densities of nanocrystalline inclusions.
Characterization of the Mobility Gap in μc-Si:H Pin Devices
Authors: Pieters Bart Elger , Schicho Sandra , Stiebig Helmut 
Published: April 2011

ABSTRACTFor the mobility gap of hydrogenated micro-crystalline silicon (μc-Si:H) a value near 1.1 eV is commonly found, similar to the bandgap of crystalline silicon. However, in other studies mobility gap values have been reported to be in the range of 1.48-1.59 eV. Indeed, for accurate modeling of μc-Si:H solar cells it is paramount that key parameters like the mobility gap are accurately determined. In this work we will discuss a method to determine the mobility gap of μc-Si:H using the dark current activation energy of μc-Si:H pin devices, and apply this method to μc-Si:H solar cells with varying crystalline volume fraction. We found the mobility gap is around 1.2 eV to 1.26 eV for μc-Si:H solar cells with a crystalline volume fraction between 50 % and 70 %. For a highly crystalline solar cell we found a mobility gap of 1.07 eV.
Doping Effects in Co-deposited Mixed Phase Films of Hydrogenated Amorphous Silicon Containing Nanocrystalline Inclusions
Authors: Blackwell C. , Pi Xiaodong , Kortshagen U. , Kakalios J. 
Published: April 2011

ABSTRACTHydrogenated amorphous silicon films containing silicon nanocrystalline inclusions (a/nc-Si:H) that have been n-type doped have been synthesized using a dual-plasma co-deposition system. We report the structural and electronic properties of n-type doped a/nc-Si:H as a function of phosphine doping level and nanocrystalline concentration. The volume fraction of nanocrystals in the doped a/nc-Si:H thin films is measured using Raman spectroscopy, and the hydrogen binding configurations are characterized using infra-red absorption spectroscopy. In undoped a/nc-Si:H, the inclusion of low and moderate nanocrystalline concentrations results in an increase in the dark conductivity, compared to a-Si:H films grown without nanocrystalline inclusions. In contrast, the addition of even a low concentration of silicon nanoparticles in doped a/nc-Si:H thin films leads to a decrease in the dark conductivity and photoconductivity, compared to pure a-Si:H films.
Seeding Solid Phase Crystallization of Amorphous Silicon Films with Embedded Nanocrystals
Authors: Anderson Curtis , Kortshagen Uwe 
Published: April 2011

ABSTRACTSilicon nanocrystals with diameters up to 30 nm are used as nucleation seeds for fast solid phase crystallization of amorphous silicon films. Purely amorphous films required an incubation time of up to 12 hours at 600°C prior to the onset of nucleation, while films with nanocrystals embedded between layers of amorphous silicon grew immediately upon annealing in a quartz tube furnace. Structural characterization was performed by heated-stage transmission electron microscopy and Raman spectroscopy.
Transient Photoconductivity Study of the Distribution of Gap States in 100°C VHF-deposited Hydrogenated Silicon Layers
Authors: Brinza Monica , Adriaenssens Guy J. , Rath Jatindra K. , Schropp Ruud E.I. 
Published: April 2011

ABSTRACTThe energy distribution of gap states has been examined by means of transient photocurrent measurements in a series of 100°C VHF-deposited Si:H samples that spans the amorphous to microcrystalline transition. The ‘amorphous’ distribution, consisting of a continuous background and a prominent dangling-bond-induced peak, remains largely intact across the transition. The transport path located at the conduction band edge in a-Si:H, some 0.63 eV above the dangling bond D− energy, moves down to ∼0.55 eV above the corresponding D− level in the microcrystalline samples.
Multilayered a-SiC:H device for Wavelength-Division (de)Multiplexing applications in the visible spectrum
Authors: Vieira Manuela , Fernandes Miguel , Louro Paula , Vieira Manuel Augusto , Barata Manuel , Fantoni Alessandro 
Published: April 2011

ABSTRACTA multiplexer is a device that combines two or more signals onto a single output without losing their specificity. In this paper we present results on the use of multilayered a-SiC:H heterostructures either as wavelength-division multiplexing or demultiplexing device (WDM). The WDM is a glass/ITO/a-SiC:H (p-i-n)/ a-SiC:H(-p) /Si:H(-i)/SiC:H (-n)/ITO double heterostructure which faces the modulated light incoming together from different beams, each one with a specific wavelength and period. By reading out, at different applied bias, the photocurrent generated by all the incoming optical carriers, the information is multiplexed or demultiplexed and can be transmitted and recovered again. The devices were characterized through spectral response measurements, under different electrical bias and frequencies. Results show that in the multiplexing mode the output signal is balanced by the wavelength of each incoming optical carrier and modulated by their frequencies. In the demultiplexing mode the photocurrent is controlled by the applied voltage and optical bias allowing to regain the transmitted information. An electrical model is presented to explain the device operation.
Magnetic Resonance in Hydrogenated Nanocrystalline Silicon Thin Films
Authors: Su Tining , Ju Tong , Yan Baojie , Yang Jeffrey , Guha Subhendu , Taylor P. Craig 
Published: April 2011

ABSTRACTWe have investigated the localized electronic states in mixed-phase hydrogenated nanocrystalline silicon thin films (nc-Si:H) with electron-spin-resonance (ESR). The dark ESR signal most likely arises from defects at the grain boundaries or within the crystallites. With illumination with photon energies ranging from 1.2 eV to 2.0 eV, there is no evidence of photo-induced carriers trapped in the bandtail states within the amorphous region. Dependence of the light-induced ESR (LESR) upon the exciting photon energy reveals that, at different excitation photon energies, different regions dominate the optical absorption. This behavior may have potential consequences for understanding the light-induced degradation in nc-Si:H.
Blue and Yellow Electroluminescence of MOSLED Made on Si-rich SiOx Film with Detuning Buried Si Nanoclusters Size
Authors: Lin Gong-Ru , Liu Chi-Wee , Hsieh Chin-Hua , Chou Li-Jen , Lin Gong-Ru 
Published: April 2011

ABSTRACTWe have demonstrated the blue and yellow electroluminescence of MOSLEDs made on Si-rich SiOx film with buried Si nanoclusters of different sizes. The situation of dehydrogenation of Si nanocrystals within the SiOx film becomes more pronounced then the re-growth of SiO2 matrix along with the prolongation of annealing time period. A linear variation on the O/Si composition ratio of the Si-rich SiOx film related to the deposition recipe is reported, giving rise to the precipitation of Si nanocrystals with different size. With such synthesis conditions, the SiOx films result in relatively strong photoluminescence at blue and yellow colors. From the comparison of the I–V curves we can conclude that there is a linear decrease on the threshold voltage of the SiOx based MOSLEDs by decreasing the thickness of the SiOx layer. According to EL pattern, we could demonstrate that the yellow- and blue-light pattern can be observed at 5.5 and 7.25 MV/cm, respectively.
Hysteresis Phenomenon in Sequential Lateral Solidification poly-Si Thin Film Transistor at low temperature (213K)
Authors: Choi Sung-Hwan , Park Sang-Geun , Lee Won-Kyu , Ha Tae-Jun , Han Min-Koo 
Published: April 2011

ABSTRACTWe have investigated temperature dependence on the hysteresis phenomenon of SLS poly-Si TFT on a glass substrate, extremely at low temperature (213K). The p-type sequential lataral solidification (SLS) polycrystalline Silicon (poly-Si) TFT was fabricated on glass substrate. As the temperature was reduced, it was observed that hysteresis phenomenon was increased, whereas the hysteresis was suppressed at high temperature. This could be explained by a difference of initially electron and hole trapped charges into gate insulator is much larger in low temperature than in high temperature. And we have verified that drain current was changed with a different previous gate starting voltage even at same bias condition by experimental results due to the hysteresis phenomenon of SLS poly-Si TFT. Hysteresis of SLS poly-Si TFT should be improved for a pixel element of high quality AMOLED display.
Luminescent Colloidal Silicon Nanocrystals Prepared by Nanoseconds Laser Fragmentation and Laser Ablation in Water
Authors: Svrcek Vladimir , Mariotti Davide , Hailstone Richard , Fujiwara Hiroyuki , Kondo Michio 
Published: April 2011

ABSTRACTThe surface states of silicon nanocrystals (Si-ncs) considerably affect quantum confinement effects and may determinate final nanocrystals properties. Colloidally dispersed Si-ncs offer larger freedom for surface modification compared to common plasma enhanced chemical vapor deposition or epitaxial synthesis in a solid matrix. The Si-ncs fabrication and elaboration in water by pulsed laser processing is an attractive alternative for controlling and engineering of nanocrystal surface by environmentally compatible way. We report on the possibility of direct silicon surface ablation and Si-ncs fabrication by nanosecond pulsed laser fragmentation of electrochemically etched Si micrograins and by laser ablation of crystalline silicon target immersed in de-ionized water. Two nanosecond pulsed lasers (Nd:YAG, and excimer KrF) are successfully employed to assure fragmentation and ablation in order to produce silicon nanoparticles. Contrary to the fragmentation process, which is more efficient under Nd:YAG irradiation, the laser ablation by both lasers led to the fabrication of fine and room temperature photoluminescent Si-ncs. The processing that has natural compatibility with the environment and advanced state of fabrication technologies may imply new possibilities and applications.
Monolithic 3D Integration of Single-Grain Si TFTs
Authors: Mofrad Mohammad Reza Tajari , Ishihara Ryoichi , Derakhshandeh Jaber , Baiano Alessandro , van der Cingel Johan , Beenakker Cees 
Published: April 2011

ABSTRACTVertical stacking of transistors is a promising technology which can realize compact and high-speed integrated circuits (ICs) with a short interconnect delay and increased functionality. Two layers of low-temperature fabricated single-grain thin-film transistors (SG TFTs) have been monolithically integrated. NMOS mobilities are 565 and 393 cm2/Vs and pMOS mobilities are 159 and 141 cm2/Vs, for the top and bottom layers respectively. A three-dimensional (3D) inverter has also been fabricated, with one transistor on the bottom layer and the other on the top layer. The inverters showed an output voltage swing of 0 to 5 V with a switching voltage of around 2 V.
Determination of the Core-structure of Shockley Partial Dislocations in 4H-SiC
Authors: Chen Yi , Zhang Ning , Huang Xianrong , Caldwell Joshua D , Liu Kendrick X , Stahlbush Robert E , Dudley Michael 
Published: April 2011

ABSTRACTSynchrotron x-ray topographs taken using basal plane reflections indicate that the electron-hole recombination activated Shockley partial dislocations in 4H silicon carbide bipolar devices appear as either white stripes with dark contrast bands at both edges or dark lines. In situ electroluminescence observations indicated that the mobile partial dislocations correspond to the white stripes in synchrotron x-ray topographs, while immobile partial dislocations correspond to the dark lines. Computer simulation based on ray-tracing principle indicates that the contrast variation of the partial dislocations in x-ray topography is determined by the position of the extra atomic half planes associated with the partial dislocations lying along their Peierls valley directions. The chemical structure of the Shockley partial dislocations can be subsequently determined unambiguously and non-destructively.
Factors Influencing the Growth Rate, Doping, and Surface Morphology of the Low-Temperature Halo-Carbon Homoepitaxial Growth of 4H SiC with HCl Additive
Authors: Melnychuk Galyna , Lin Huang De , Kotamraju Siva Prasad , Koshka Yaroslav 
Published: April 2011

ABSTRACTIn this work, a possibility to further suppress silicon vapor condensation and formation of Si clusters in order to improve the growth rate and morphology during the low-temperature halo-carbon epitaxial growth of 4H-SiC was investigated. While a pronounced dissociating of Si clusters was clearly demonstrated, the enhancement of the growth rate and morphology was less significant then expected. In addition, the homogeneity of the growth rate and doping along the gas flow direction indicated that a significant and non-equal depletion of Si and C growth species takes place at sufficiently high HCl supply. HCl flow-dependent formation of polycrystalline Si and SiC deposits in the upstream portion of the hot zone was shown to be the source of this depletion.
Effect of SiC Power DMOSFET Threshold-Voltage Instability
Authors: Lelis Aivars , Habersat D. , Green R. , Ogunniyi A. , Gurfinkel M. , Suehle J. , Goldsman N. 
Published: April 2011

ABSTRACTWe have performed bias-stress induced threshold-voltage instability measurements on fully processed 4-H SiC power DMOSFETs as a function of bias-stress time, field, and temperature and have observed similar instabilities to those previously reported for lateral SiC MOSFET test structures. This effect is likely due to electrons tunneling into and out of near-interfacial oxide traps that extend spatially into the gate oxide. As long as the threshold voltage is set high enough to preclude the onset of subthreshold drain leakage current in the blocking state, then the primary effect of this instability is to increase the on-state resistance. For well-behaved power DMOSFETs, this would increase the power loss by no more than a few percent.
Performance Characteristics of 65nm PFETs Using Molecular Implant Species for Source and Drain Extensions
Authors: Tan Chung Foong , Teo L. W. , Yin C-S. , Lee J. G. , Liu J. , See A. , Zhou M. S. , Quek E. , Chu S. , Hatem C. , Variam N. , Arevalo E. , Gupta A. , Mehta S. 
Published: April 2011

ABSTRACTWe investigated the performance of 65nm pFETs whereby the source and drain extensions (SDE) were implanted with Carborane, (C2B10H12) a novel form of molecular species. The high atomic mass of this molecule (146 a.m.u.) and the number of boron atoms transported per ion enables the productivity at low energy required for manufacturing of ultra shallow junctions for advanced scaling. In this investigation, Carborane was implanted at 13 keV to produce a Boron profile near equivalent to that produced by the reference BF2 implant. Results of electrical measurements did not exhibit any compromise in the I-V characteristics in terms of Id-Vg and Id-Vd and Ion-Ioff. External resistance and Vt roll-off shifted slightly with respect to the reference devices. This is attributed to a deeper junction with Carborane due to slight offset in the profile matching. It will be shown that with fully matched profiles, a perfect match of the device characteristics can be achieved.
Doping of Sub-50nm SOI Layers
Authors: Pawlak Bartek J. , Duffy Ray , van Dal Mark , Voogt Frans , Weemaes Robbert , Roozeboom Fred , Zalm Peer , Bennett Nick , Cowern Nick 
Published: April 2011

ABSTRACTDoping of thin body Si becomes very essential topic due to increasing interest of forming source/drain regions in fully depleted planar silicon-on-isolator (SOI) devices or vertical Fin field-effect-transistors (FinFETs). To diminish the role of the short-channel-control-effect (SCE) the Si layers thicknesses target the 10 nm range. In this paper many aspects of thin Si body doping are discussed: dopant retention, implantation-related amorphization, thin body recrystallization, sheet resistance (Rs) and carrier mobility in crystalline or amorphized material, impact of the annealing ambient on Rs for various SOI thicknesses. The complexity of 3D geometry for vertical Fin and the vicinity of the extended surface have an impact on doping strategies that are significantly different than for planar bulk devices.
Boron Enhanced H Diffusion in Amorphous Si Formed by Ion Implantation
Authors: Johnson Brett Cameron , Atanacio Armand J. , Prince Kathryn E. , McCallum Jeffrey C. 
Published: April 2011

ABSTRACTBoron enhanced H diffusion in amorphous Si (a-Si) layers formed by ion implantation is observed using secondary ion mass spectroscopy (SIMS). Constant concentrations of B were achieved using multiple energy B implantations into thick a-Si layers. The evolution of single H implanted profiles centered on the uniformly B-implanted regions was studied for partial anneals at temperatures in the range 380 – 640 °C. Boron enhanced diffusion is observed and the enhanced diffusion coefficient shows trends with temperature typically associated with a Fermi level shifting dependence. A modified form of the generalized Fermi level shifting model is considered in light of these results.
Intrinsic and Dopant-Enhanced Solid Phase Epitaxy in Amorphous Germanium
Authors: Johnson Brett Cameron , Gortmaker Paul , McCallum Jeffrey C. 
Published: April 2011

ABSTRACTThe kinetics of intrinsic and dopant-enhanced solid phase epitaxy (SPE) are studied in thick amorphous germanium (a-Ge) layers formed by ion implantation on <100> Ge substrates. The SPE rates for H-free Ge were measured with a time-resolved reflectivity (TRR) system in the temperature range 300 – 540 °C and found to have an activation energy of (2.15 ± 0.04) eV. Dopant enhanced SPE was measured in a-Ge layers containing a uniform concentration profile of implanted As spanning the concentration regime 1 – 10 × 1019 cm3. The generalized Fermi level shifting model shows excellent fits to the data.
Atomistic Modeling of {311} Defects and Dislocation Ribbons
Authors: Trzynadlowski Bart , Dunham Scott , Ahn Chihak 
Published: April 2011

ABSTRACTAb-initio calculations of dislocation and {311} defect structures in silicon were performed in order to investigate the formation energies as functions of geometry, including the effects of applied strain, with a simple model. Predictions were made concerning the size at which a {311} defect becomes less favorable than a dislocation loop, and it was shown that this is affected by applied strain.