bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Tentative Identification of Certain Deep Levels in GaAs and Related Compounds
Authors: Yuanxi Zou , Yuanhsi Chou , Peigen Mo , Qianzhi Yang , Huifang Min , Guicheng Zhang 
Published: March 2011

AbstractSome recent data on minority carrier diffusion length MCDL in GaAs and certain optoelectric parameters of LEDs obtained by the authors as well as reported in the literature have been analysed to shed light on the probable configuration of certain deep levels in GaAs and related compounds. The practical implications of the results obtained are discussed from the view point of the mechanism of slow degradation of the related optoelectronic devices.
Excitation Spectroscopy on Silicon Using Color Center Lasers Study of the Thermally Induced P Line (0.767eV) Defect
Authors: Wagner J. , Dörnen A. , Sauer R. 
Published: March 2011

AbstractRecently developed tunable color center lasers allow to extend the experimental technique of excitation spectroscopy to the 1–2 μm region. This spectral range is of special interest for the study of luminescent defects in silicon. We discuss the color center laser systems available at present and their application to defect spectroscopy. As an example, results on the 0.767 eV (P line) defect in silicon are presented. Excitation spectroscopy reveals several high lying excited electronic states. They are interpreted as effective—mass—like states of a pseudo-donor with an ionization energy of 34.3 meV.
Electronic Structure of Deep-Lying Sulfur Centers in Si
Authors: Zeiger H. J. , Kleiner W. H. 
Published: March 2011

AbstractA theoretical analysis has been made of infrared absorption spectra measured earlier for four deep-lying sulfur centers in Si. The data consist of absorption frequencies and polarization selection rules determined for uniaxial stress applied along [001], [111], and [110] axes. Both ls + np transitions and ls → ls transitions are observed. The A and B centers (binding energies 0.1090 eV and 0.1872 eV, respectively) are found to be He-like, while the C and D centers (binding energies 0.3683 eV and 0.6116 eV, respectively) are found to be He+-like. The D center spectra are consistent with Td symmetry, while the A, B and C spectra are consistent in most respects with C3v or D3d symmetry. One noteworthy result is the finding that the ls + np spectral frequencies observed under stress for the A center are consistent with a ls(E) ground state.
Structural and Electrical Characterization of Polycrystalline Semiconductor Materials
Authors: Matson Richard J. , Tsuo Y. Simon 
Published: March 2011

AbstractSecondary electron imaging, electron channeling and electron-beaminduced current (EBIC) are used alternately in a scanning electron microscope to characterize and correlate the morphology, crystallographic orientation, and electronic quality (types and spatial distribution of defects) of individual grains in polycrystalline semiconductor samples. The technique is discussed in some detail, and a number of applications and results in the study of edge-supported-pulling (ESP) silicon sheet and low-angle silicon sheet (LASS) materials are reported.
Crystallization of Ge-Rich Amorphous Mo-Ge Alloys
Authors: Marshall Ann F. , Yoshizumi S. 
Published: March 2011

ABSTRACTThe crystallization behavior of amorphous Mo-Ge alloys in the Ge-rich region have been characterized by resistivity measurements and transmission electron microscopy (TEM). Alloys with compositions in the metalsemiconductor transition region, where two distinct types of SRO occur, show compositional segregation on a fine scale during the first transformation step. Alloys in the adjacent composition region, where SRO is similar to the intermetallic compounds, crystallize polymorphically into metastable structures based on the equilibrium intermetallic structures. The resistivity characteristics and the relationship between the amorphous and partially transformed structures are discussed.
The Relationship of Structure to Properties in Electrodeposited Films
Authors: Sheppard Keith , Weil Rolf 
Published: March 2011

ABSTRACTThe recent development of a more systematic, scientific basis for knowledge in electrodeposition technology is discussed, focussing on the influence of microstructure on deposit properties. Internal stresses, tensile strength, ductility, preferred orientation and the ability to electrodeposit amorphous materials are considered. In particular the unique influence on these properties of small quantities of chemical additives is discussed. The application of current modulation techniques during electrodeposition is described as an alternative means of controlling structure and properties.
Characterization of W-N Alloys Formed By Sputter Deposition
Authors: Affolter K. , Kattelus H. , Nicolet M-A. 
Published: March 2011

ABSTRACTThin films of W-N alloys have been prepared by reactive rf sputtering from a W target. Alloy compositions up to about 65at.%N, amorphous phases are formed with crystallization temperatures up to above 600°C. All the films gradually release N upon vacuum annealing and decompose into αW between 700 and 800°C in vacuo. Application of W-N alloys as diffusion barriers in a Si metallization scheme is discussed.
Chemical Composition and Electrical Behavior of Contacts on Highly and Moderately Silicon-Doped (100) GaAs
Authors: Holloway P. H. , Wang Y. -X. , Xie Y. -J. , Bussing T. D. 
Published: March 2011

ABSTRACTThe effects of 1 to 5 keV Ar+ sputtering of (100) GaAs doped with >3 × 1018 cm−3 or <2 × 1017 cm−3 Si and contacted with 1000 Å of Au have been studied. Sputtering caused the contacts on highly doped GaAs to change from ohmic to rectifying, while it caused the Schottky barrier height on moderately doped GaAs to decrease. For both doping densities, barrier heights of ∼0.6 eV were measured. Inverse Laplace transform analysis of angle-resolved X-ray photoelectron spectroscopy data showed that As was preferentially sputtered, probably by a damage-assisted Gibbsian surface segregation mechanism. Modifications of the electrical contacts were explained by sputter-induced self-compensation by Si rearrangement and by damage-created shallow donors with a density of >2 × 1017 cm−3.
Structural Studies of an InAs-GaAs Superlattice Alloy
Authors: Tamargo M. C. , Hull R. , Greene L. H. , Hayes J. R. , Tabatabaie N. , Cho A. Y. 
Published: March 2011

ABSTRACTThin alternating layers of InAs and GaAs have been grown by MBE on buffer layers lattice matched to InP. The layer structure was evaluated by transmission electron microscopy (TEM) and low angle X-ray scattering. Commensurate epitaxial layers approximately 15Å thick were obtained in spite of the large lattice mismatch (7%). These results and their implication for growth conditions of strained-layer superlattices will be discussed.
Ion-Beam Deposition of Thin Films:Influence on Surface and Volume Microstructure
Authors: Al-Jumaily G. A. , Mcnally J. J. , Mcneil J. R. 
Published: March 2011

ABSTRACTThe effects of ion bombardment during film deposition on surface and volume microstructure were studied. Both metal and dielectric films were investigated. Scattered light and optical constants were examined for evaporated, sputtered and ion assisted films.
Local Bonding in A—Sige Alloy Films
Authors: Lucovsky G. , Rudder R.A. , Cook J.W. , Lin S.Y. 
Published: March 2011

AbstractThis paper discusses the bonding of hydrogen in a—Si,Ge:H alloy films prepared byreactive magnetron sputtering (RMS). We compare our results for H atom bonding with films produced by: (a) the glow discharge decomposition (GDD) of silane and germane mixtures, and (b) reactive diode sputtering (RDS). We discuss the energy states associated with Si and Ge atom nfeutrat angling bonds in the context of an empirical tight—binding modeL The model places the Ge atom dangling bond state deeper in the gap than the corresponding Si atom defect state. The differences between the electronic properties of GDDand RDS films, and R4S films are explained in terms of the degree of H compensation of Si and Ge atom dangling bonds.
Properties of Intrinsic a-Si Films Deposited From Higher Order Silanes by Chemical Vapor Deposition
Authors: Rocheleau Richard E. , Hegedus Steven S. , Baron Bill N. 
Published: March 2011

AbstractAmorphous silicon films have been deposited by chemical vapor deposition using disilane at temperatures between 360 and 525°C at growth rates up to 50 A/s. Intrinsic films have the following properties: σp less than 5 × 10−6 (Ω-cm)−l; σd less than 5 × 10−11 (Ω-cm)−1 with Ea = 0.7 to 0.8 eV; diffusion length around 0.1 μm; Urbach energy 48 to 55 meV; and mid-gap density of states greater than 5 × 1016 cm−3 eV−1. Boron compensation improved collection efficiency by lowering the mid-gap density of states, not by improving the μτ product. Pin cells with effíciencies of 4% and Jsc = 10.9 mA/cm2 (87.5 mW ELH) were fabricated.
Photo—Conductive Amorphous Silicon Carbide Prepared by Intermediate Species SiF2 and Cf4 Mixture
Authors: Matsumura Hideki , Uesugi Takashi , Ihara Hisanori 
Published: March 2011

AbstractA new type of hydro—fluorinated amorphous silicon—carbide (a-SiC:F:H) is produced by the glow discharge decomposition of gas mixture of CF4, H2 and intermediate species SiF2. The electrical, optical and structural properties of this a—SiC:F:H are studied and the results are compared with the similar results for a—SiC:F:H produced from gas mixture of CH4, H2 and SiF2 and also for hydrogenated amorphous silicon carbide (a—SiC:H) produced from CH4 and SiH4 gas mixture. It is found that the optical band gap can be increased without degradation of photo—conductive properties only when amorphous silicon carbide is produced from CF4, H2 and SiF2 gas mixture.
Recent Progress of Amorphous Silicon Solar Cell Technology
Authors: Hamakawa Y. 
Published: March 2011

AbstractA review is given on recent progress in the amorphous silicon solar cells and their technologies. Firstly, some unique advantages of amorphous silicon as a low cost solar cell material are pointed out, and its significant position in the photovoltaic project are discussed. Secondly, newly developed key technologies for improving the photovoltaic performance are demonstrated from the film quality improvement to new junction structure solar cells with a wide and narrow energy gap amorphous silicon alloys. Then, current state of the art in the cell performance are summarized. In the final part, recent feature of the industrializations in both consumer and power application fields are overviewed.
Dual-Chamber Plasma Deposition of a-Si:H Solar Cells at High Rates Using Disilane
Authors: Rajeswaran G. , Vanier P.E. , Corderman R.R. , Kampas F.J. 
Published: March 2011

AbstractThe use of a separated chamber deposition system for the fabrication of a-Si:H solar cells from disilane at high deposition rates results in a substantial improvement in short circuit current compared to that obtained from a single-chamber system. The spectral responses of cells fabricated in the dual-chamber mode are compared to those made in the single-chamber mode. The results are interpreted by assuming that the rate of removal of boron contaminants from the chamber is independent of deposition rate.
Research Progress in the Doe/Seri Amorphous Silicon Research Project
Authors: Sabisky E. , Wallace W. , Stafford B. , Sadlon K. , Luft W. 
Published: March 2011

AbstractThe Amorphous Silicon Research Project (ASRP), established at the Solar Energy Research Institute (SERI) in 1983, is responsible for all U.S. DOE government supported research activities in the field of amorphous silicon photovoltaics. The objectives and research directions of the project have been established by a Five Year Research Plan developed at SERI in cooperation with the Department of Energy in 1984. In order to accomplish project goals, research is performed by a combination of i) multi-year programs consisting of multi-disciplinary research teams based on strong government/industry partnerships and ii) basic research performed in university, government and industrial laboratories. A summary of recent research progress in the ASRP program is presented.
Thermodynamic Study of Silane-hydrogen Chemical System
Authors: Patel Rajendra I. 
Published: March 2011

AbstractThe thermodynamic calculations of chemical equilibrium compositions of various species were performed for silane-hydrogen system at different temperatUres [500-6000K], pressures [0.01-10 Torr], and mixing ratios [various silane fractions]. The effect of dopant impurities such as diborane and phosphine on equilibrium concentration profiles of various gaseous, tonic, and condensed species was also investigated. These data will be very useful in understanding the deposition chemistry of silane chemical systems and will be a valuable aid in optimization studies.
Capacitance Studies of Light-Induced Effects in Undoped Hydrogenated Amorphous Silicon
Authors: Zellama K. , Cohen J.D. , Harbison J.P. 
Published: March 2011

AbstractThe effects of light saturation on the properties of undoped a-Si:H films were studied by a new capacitance profiling technique which can be used to directly determine changes in the dangling bond density of states near midgap. Coplanar conductivity and capacitance vs. temperature measurements save the changes in activation energies for electrical conductivity. These studies indicate that, while substantial increases in the dangling bond densities are observed for most samples, the detailed behavior of the light induced changes in these films are inconsistent with the creation of such defects by breaking weak valence band tail states.
Amorphous Silicon Films and Solar Cells Prepared by Mercury-Sensitized Photo-CVD of Silane and Disilane
Authors: Delahoy Alan E. , Doele B. , Ellis F.B. , Ramaprasad K.R. , Tonon T. , Dine J. Van 
Published: March 2011

AbstractThe low temperature deposition of a-Si:H films and devices by mercurysensitized photo-decomposition of silanes is described. The problem of window deposition is ameliorated by the use of a perfluoropolyether coating to give deposition rates of 0.3 Å s−1. Highly photosensitive undoped layers can be produced. These films exhibit many properties in common with glow discharge films including thermal quenching of photoconductivity between 125-200°K and the Staebler-Wronski effect. A wide gap silicon carbide p layer is described, and is usefully employed in p-i-n structures to give 6% efficient solar cells. SIMS analysis of these devices shows that it is possible to achieve sharp p-i interfaces in a single chamber reactor. Deposition rates greater than 2 As−1 have recently been achieved.
Short Channel Amorphous Silicon MOS Structures with Reduced Capacitance
Authors: Yaniv Z. , Cannella V. , Hansell G. , Vijan M. 
Published: March 2011

AbstractWe report improvements in device structures by the reduction of capacitance in short channel length thin film transistors of amorphous silicon alloy materials. Employing techniques similar to those previously reported [1,2], these MOS structures are fabricated with channel lengths of 1 to 2 micrometers using standard photolithography with 10 micrometer minimum feature size. Significant reductions in capacitance over earlier reported device designs were achieved by improvements in device geometry and innovative use of shadowing techniques utilizing oblique angle deposition to minimize overlap between electrodes. Theses reduced capacitance short channel length TFTs enhance the possibility of fabricating on-board drivers for active matrix liquid crystal displays using amorphous silicon alloy devices. Despite the relatively low mobility of amorphous silicon (∼ 1 cm2 /V-sec) these short channel length TFTs can provide currents large enough for operation in the megahertz regime when these reductions in capacitance are incorporated. The noncritical photolithography assures that devices may be fabricated over large area substrates (8" × 8") with acceptable yields. Computer simulations predict that these TFTs will be able to provide the necessary speed for on-substrate drivers. We will present experimental results from the new TFT structures and describe modeling methods and results for amorphous silicon TFT ring oscillators. We will discuss the significance of these results as they pertain to drive circuitry for large area liquid crystal displays.
A High-Speed Amorphous-Silicon Dytamic Circuit
Authors: Okada H. , Nara Y. , Uchida Y. , Watanabe Y. , Matsumura M. 
Published: March 2011

AbstractA novel dynamic circuit composed of amorphous-silicon Schottkybarrier diodes and field-effect transistors has been proposed. The circuit response time is as short as the discharging time of a load capacitor through the driver transistor. The circuit having 1µm-long, self-aligned transistors has been predicted theoretically to be able to be operated at multi-MHz rates. Preliminary experimental results are also presented.
Influence of Transparent Electrodes on Image Sensor Performance
Authors: Kempter K. , Wieczrek H. , Hoheisel M. 
Published: March 2011

AbstractThe short response times required for image sensors demand blocking contacts at the sensor cell. It was found that the junctions between transparent electrodes (ITO or a thin palladium film) and the metallic back electrode with a-Si:H form blocking contacts yielding photocurrent decay times of the order of some microseconds. The two different time regimes observed for the decay are interpreted as being limited by the drift and the release of holes respectively.
The Use of Amorphous Silicon Emitters in Bipolar Transistors
Authors: Ghannam M. , Nijs J. , Keersmaecker R. De , Mertens R. 
Published: March 2011

AbstractFor the first time an operating heterojunction bipolar silicon transistor has been realized with phosphorous doped amorphous silicon (a-Si) emitter. The deposition of a-Si is a relatively simple technique. The current gain (β) of 14 at a base Gummel Number (G.N.) of 1.35 1013 s/cm4 is higher than that obtained with normal diffused emitter bipolar transistors with the same G.N. for the base. This adds a degree of freedom to the design of bipolar structures according to the compromise between base resistance and current gainCrucial points that have to be looked at further are interface recombination at the a-Si/c-Si transition and emitter resistance.
Recombination Under Double Injection Conditions in a-Si:H Based Diodes.
Authors: Konenkamp R. , Madan Arun 
Published: March 2011

AbstractThe junction recovery technique is used to investigate recombination parameters and kinetics in thin film a-Si:H diodes. It is found that double injection occurs in most of the p-i-n type samples at sufficient forward bias and that the recovery currents are dominated by the extraction of trapped holes from the valence bandtail. The mobility-lifetime product of the recovered carriers is seen to be strongly dependent on the dopant concentration in the active layers of the devices.
Steady State and Transient Capacitance Measurements of the Energy Levels of a Low Angle Tilt Boundary in a Germanium Bicrystal
Authors: Broniatowski A. , Bourgoin J.C. 
Published: March 2011

ABSTRACTSteady state and transient capacitance (DLTS) measurements have been performed on a low angle tilt boundary in a germanium bicrystal, in combination with an electron microscope study of the boundary dislocation structure. A characteristic level has been found at 0.42 eV below the bottom of the conduction band, with a density about 109 cm-2 and an electronic capture cross-section about 5 × 10-12 cm2.
Experimental Study of the Relative Energy of Symmetrical <110> Tilt Boundaries in a Semi-Conducting F.C.C. Oxide (NiO).
Authors: Dhalenne Guy , Dechamps Michel , Revcolevschi Alexandre 
Published: March 2011

ABSTRACTLarge size bicrystalline samples of NiO corresponding to tilt configurations around a < 110 > axis have been grown by the flame fusion technique, the misorientation angles varying from 0 to 180°. The variation of the relative energy of the grain boundary with misorientation has been studied and has indicated a very different behaviour from that previously observed by the authors on <100> tilt boundaries. High relative energy values and deep cusps on the energy curve at high coincidence angles are observed. The results are discussed in terms of interface energy.
Identification of Arsenic Surface Species on the Si (100) Surface
Authors: Perino S. C. , Helms C. R. 
Published: March 2011

ABSTRACTThe molecular character of arsenic adsorbed on the Si (100) surface has been investigated using thermal desorption spectroscopy (TDS) and Auger electron spectroscopy (AES). A variety of arsenic surface species were deposited on the silicon surface by employing different evaporation sources, including metallic arsenic, arsine gas, and chips of GaAs crystals. We present coverage dependent spectra showing the desorption of As4 tetramers at 350°C and As2 dimers at 900°C. The loosely bound arsenic is adsorbed from the solid evaporation sources only and resides on the surface as tetramers. The tightly bound arsenic does not form multiple layers and the high desorption temperatures suggests the adsorbed arsenic exists as monomers.
The Effect of Heat Treatment on Grain Boundary Properties in Cast Polycrystalline Silicon
Authors: Russell P.E. , Herrington C.R. , Burke D.E. , Holloway P.H. 
Published: March 2011

ABSTRACTThe effects of heat treatment at temperatures appropriate for solar cell device fabrication on grain boundaries in cast poicrystalline silicon have been studied. An MIS device structure using a 200° C heating was used for fabricating test devices on heat treated samples for EBIC studies. Grain boundary effective surface recombination velocities (Seffgb ) and effective mid-grain diffusion lengths were measured. Seffgb was found to increase after heat treatment. Segregation of oxygen to grain boundaries has been observed in heat treated samples.
Grain Boundary Shunt Currents Across a pn Junction
Authors: Roy Morrison S. 
Published: March 2011

ABSTRACTThe effect on the diode characteristics when a conducting grain boundary intersects a pn junction is analyzed. The possibilities of conducting grain boundaries are related to the levels associated with precipitates at the grain boundary. The effect of the grain boundary on the diode characteristics is found particularly degrading when donor impurities precipitate in the n region while simultaneously acceptor impurities precipitate in the p region. Both solar cell characteristics and the dark diode characteristics are analyzed.
Chemical and Ion Beam Etch Studies of Polycrystalline Silicon
Authors: Lester P. A. , Singh R. , Rice D.A. , Pangborn R. N. , Ashok S. , Fonash S. J. 
Published: March 2011

ABSTRACTMS and MIS solar cell performance as a function of wet chemical etching history has been studied and correlated with lattice strain obtained from x-ray double-crystal diffraction technique and intragranular surface topography. Dry ion beam etching from a Kaufman ion source is found to damage the surface and radically alter the electrical barrier by introducing donor-like states in the damaged region.
Grain Boundary Passivation and Analysis for Solar Cell Applications
Authors: Rao V. J. , Anderson W. A. , Kai F. 
Published: March 2011

ABSTRACTGrain boundaries in Wacker poly-Si are shown to contribute mid-gap interface states, a greater frequency dependence in a.c. conductance, and lesser frequency dependence in capacitance. H-passivation was shown to be effective in reducing grain boundary effects as evidenced by 4-point probe resistance and IR studies.