bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficient Si solar cells by low-temperature solid-phase epitaxy
Authors: Tsaur B-Y. , Turner G. W. , Fan John C. C.
Published: February 2003

Solid-phase epitaxial Si layers of uniform thickness have been grown at 400–500 °C by transport of Si atoms from an amorphous Si film through an Al film deposited on 〈100〉 single crystal or polycrystalline n-type Si substrates. The epitaxial Si layers are strongly p type due to Al doping, and good rectifying junctions are formed between these layers and the substrates. Solar cells with conversion efficiencies at AM1 of 10.4 and 8.5% have been fabricated on 〈100〉 Si and polycrystalline Si substrates, respectively, without the use of an antireflection coating or back-surface field structure.
Oxidation of silicon by ion implantation and laser irradiation
Authors: Chiang S. W. , Liu Y. S. , Reihl R. F.
Published: February 2003

Q-switched laser irradiation has been used to anneal O+-implanted silicon to form SiO2 layers. Results of differential Fourier-transformed infrared spectroscopy and transmission electron microscopy confirm the formation of oxide layers. Segregation of oxygen toward the surface was observed by secondary ion mass spectroscopy and correlated with resolidification velocities, which vary as a function of laser energy densities.
Rare-earth oxides as artificial barriers in superconducting tunneling junctions
Authors: Umbach C. P. , Goldman A. M. , Toth L. E.
Published: February 2003

Superconducting tunneling junctions have been prepared on Nb, Nb3Ge, V3Si, ErRh4B4, and Au base electrodes with either Pb or In counterelectrodes using a barrier of oxidized Er or Lu. Nb/RE/oxide/Pb Josephson junctions with very low leakage have been studied in detail. The ease of fabrication and the stability of the junctions under thermal cycling suggest that they may have technological significance.
Optical recording in hydrogenated semiconductors
Authors: Bösch M. A.
Published: February 2003

Optical information recording and storage is investigated in hydrogenated amorphous semiconductor films. The recording mechanisms are based on the evolution of hydrogen within the active layer. Three different processes are observed: (1) bulge (or bubble) formation, (2) spongelike microswelling, and (3) ablation without melting.
Short-wavelength continuous 300-K photopumped AlxGa1−xAs-GaAs quantum well heterostructure laser (λ≳7270 Å)
Authors: Morkoç H. , Drummond T. J. , Camras M. D. , Holonyak N.
Published: February 2003

Data are presented demonstrating room-temperature continuous (cw 300 K) photopumped laser operation of AlxGa1−xAs-GaAs (x∼0.4) quantum well heterostructures (QWH) at wavelengths as short as λ∼7270 Å, or h/ω−Eg (GaAs)∼280 meV. Photoexcitation levels on these six-well Lz ∼28 Å QWH’s have been as low as 5.6×103 W/cm2 or Jeq ∼2.3×103 A/cm2, which is in a practical range for cw 300-K diodes.
A variable surface acoustic wave delay line utilizing a voltage controlled air gap
Authors: Takeuchi Hiroshi
Published: February 2003

A surface acoustic wave (SAW) delay line is demonstrated which is variable and employs interaction between the SAW on a piezoelectric substrate and an adjacent electrically conductive film. With this structure, a tunability of 2.7×10−3 has been achieved by electrically controlling an air gap between a gold film and a (YZ)LiNbO3 substrate. Improvements in the air-gap fabrication techniques could increase the tunability up to ∼10−2.
Electric discharge effects on a XeCl pumped S2 heat-pipe laser
Authors: Killeen K. , Greenberg K. , Verdeyen J. T.
Published: February 2003

It is shown that an electrical discharge can dissociate the higher-order sulfur molecules S3→8 into dimers S2 and thus create the proper environment for efficient conversion of XeCl radiation at 308 nm to the blue-green. The use of a heat-pipe configuration greatly alleviates the technological problems.
Physical basis of scattering potential at grain boundary of polycrystalline semiconductors
Authors: Wu C. M. , Yang E. S.
Published: February 2003

A physical theory using a charge scattering model is proposed to interpret the experimental data of grain boundary transport in polycrystalline semiconductors. The calculated result explains the need of an attenuation factor as an added coefficient in the thermionic emission current.
Characterization of LiNbO3 waveguides exchanged in TlNO3 solution
Authors: Chen Yi-Xin , Chang William S. C. , Lau S. S. , Wielunski L. , Holman Robert L.
Published: February 2003

Characteristics of our waveguides are very different than those reported earlier by Jackel. We shall show that the waveguiding is produced by a loss of Li atoms rather than a significant indiffusion of Tl.
Schottky solar cells on thin polycrystalline Zn3P2 films
Authors: Bhushan M.
Published: February 2003

Thin, polycrystalline films of p-type Zn3P2 were grown by close-spaced vapor transport on mica substrates coated with films of Fe and Si. Schottky solar cells were prepared by sputter depositing a thin, transparent film of Mg on Zn3P2. A total area conversion efficiency of 4.3% was achieved on 1-cm2 area cell, under simulated AM1 illumination. The short-circuit current and open-circuit voltage were comparable to similar devices on single-crystal Zn3P2. The barrier height was found to be ∼1.3 eV, higher than for Mg/Zn3P2 contacts reported earlier.
Induced junction monolithic zinc oxide-on-silicon storage correlator
Authors: Weng K. C. -K. , Gunshor R. L. , Pierret R. F.
Published: February 2003

An induced junction array is proposed as an alternative to the conventional PN diode configuration in the implementation of reference storage in a surface acoustic wave SAW storage correlator. Induced junction devices fabricated in the ZnO-on-Si structure are found to exhibit performance characteristics comparable to those of PN diode correlators, while providing greater ease of fabrication.
Evidence for a parallel path oxidation mechanism at the Si-SiO2 interface
Authors: Irene E. A.
Published: February 2003

Some controversy exists as to whether the reaction of oxygen and Si at the Si-SiO2 interface involves both atomic and molecular oxygen. From the direction of curvature of Arrhenius plots for the observed rate constants substantial support is obtained for the mechanism with two oxidant species. The direction of curvature was obtained from the second derivative of In kobs with respect to T−1. Parallel rate processes yield concave upwards Arrhenius plots while consecutive processes yield concave downwards plots.
Interface recombination and carrier confinement at a GaAs/GaxIn1−xP double heterojunction studied by picosecond population modulation spectroscopy
Authors: Harris J. H. , Sugai S. , Nurmikko A. V.
Published: February 2003

Sensitive picosecond excite-probe modulation methods have been applied to study electron-hole confinement and interface lifetime in a molecular beam epitaxy (MBE) grown n-type GaxIn1−xP/ GaAs/GaxIn1−xP double heterojunction. Time-varying transmission spectra at 77 K have been examined near the E0+Δ0 transition in GaAs and near the fundamental edge in GaxIn1−xP (x = 0.47), following the injection of a small electron-hole population. We demonstrate directly the confining efficiency of the structure for electrons and, consistent with other recent evidence, find that the interface recombination velocity in the relatively strain-free heterostructure is reduced to less than 1×104 cm/s from the value of 5×105 cm/s for a free GaAs surface. The latter has been determined by us directly from time-resolved reflection spectra which suggest further applications of these methods to surface spectroscopy of semiconductors.
Output power and temperature dependence of the linewidth of single- frequency cw (GaAl)As diode lasers
Authors: Welford D. , Mooradian A.
Published: February 2003

We report here the observation of a linear dependence of cw single-frequency (GaAl)As diode laser linewidth as a function of reciprocal output power at 77, 195, and 273 K. The observed data are explained in terms of spontaneous emission events and their related refractive index perturbations.
1/f frequency fluctuations of a quartz oscillator
Authors: Noguchi Yasuaki , Teramachi Yasuaki , Musha Toshimitsu
Published: February 2003

Power spectral densities of frequency fluctuation of 5-MHz, 5th-overtone, plano-convex IT-cut quartz oscillators were evaluated for various fluctuation levels of environmental temperature. The spectrum is a superposition of two components of different origins: one depends on the temperature fluctuation level and the other does not. The temperature-independent spectrum is inversely proportional to the Fourier frequency.
Detailed characteristics of an intense proton beam from an ‘‘applied-Bϑ’’ magnetically insulated ion diode
Authors: Zieher K. W. , Hammer D. A. , Pal R. , Renk T.
Published: February 2003

Detailed structure and statistical divergence have been measured on the intense pulsed proton beam (300 keV, 80 ns, 5–10 kA) produced by an applied-Bϑ magnetically insulated ion diode. A statistical divergence of the beam of about ±2° azimuthally and ±2° to ±4° radially was obtained. Beam image patterns show an intensity modulation of the proton beam in the azimuthal direction corresponding to a period 0.5–1 mm on the anode surface in addition to a regular 6-mm modulation caused by structure built into the anode.
Experimental study of a superconducting vortex-memory device
Authors: Parisi J. , Huebener R. P. , Mühlemeier B.
Published: February 2003

A nondestructive readout random access memory based on the use of a two-dimensional array of single-quantum vortices in a thin-film type-II superconductor represents an interesting new storage medium for future Josephson computers. We have studied experimentally the operational mode of this memory device, using as a model system multiquanta flux tubes in a thin-film type-I superconductor (Pb) in combination with stroboscopic high-resolution magneto-optical flux detection. From our results estimates of the performance data of a single-quantum vortex- memory device are derived.
Pyroelectric detection of magnetic resonance
Authors: Melcher R. L. , Arbach G. V.
Published: February 2003

Magnetic resonance absorption has been detected in paramagnetic and ferromagnetic materials using pyroelectric sensing of the temperature rise of the sample. In addition to being a valuable method for thermal detection of magnetic resonance, the technique provides a useful method for the measurement of the pyroelectric properties of materials.
Anode heating by x rays in high power diodes
Authors: Wilson Andrew , Waisman Eduardo M. , Chapman Milt
Published: February 2003

We present a possible mechanism for the heating creation of anode plasma in pulsed power machines. It involves the radiation emitted by the whisker plasma situated near the surface of the opposing electrode. We show that deposited energies in excess of 400 J/g are possible in typical modern machines in regions of the vacuum feed where the pulse magnetic field attains peak values on the order of 100 kG. If the assumption is made that the initial temperature of the cathode plasma is about 5 eV and that its mass depth is in excess of 10−7 g/cm2 the anode surface is raised to over 600 °C during short (50 ns) pulses, thereby liberating desorbed gas atoms which the x rays may then ionize.
1.22-μm HgCdTe/CdTe avalanche photodiodes
Authors: Shin S. H. , Pasko J. G. , Law H. D. , Cheung D. T.
Published: February 2003

A planar HgCdTe/CdTe avalanche photodiode with peak responsivity at 1.22 μm and cutoff at 1.25 μm has been fabricated successfully by liquid phase epitaxy (LPE). Avalanche gains of higher than 15 have been obtained with 1.06-μm Nd:yttrium aluminum garnet (YAG) laser illumination. A reverse breakdown voltage of 80 V and a leakage current density of 1×10−4 A/cm2 at 40 V were measured. The peak quantum efficiency at 1.22 μm is 72% without any antireflection coating.
Efficient CdSe/p+n Si tunnel junction photoanode for solar cell
Authors: Pinson W. E.
Published: February 2003

The 1.03-V solar photoemf generated by this CdSe/p+n Si photoanode lends itself to solar storage applications. We present evidence that the 21-mA/cm2 short circuit solar photocurrent results from a low resistance tunnel path between the CdSe conduction band and the p+ Si valence band. We use the dark electron current to calculate that the hole quasi-Fermi level at the CdSe surface of the solar illuminated open circuited photoanode lies 0.16 V below the CdSe corrosion potential. Hence even on open circuit the CdSe surface of the illuminated photoanode will corrode.
Geminate recombination-controlled photogeneration in amorphous solids
Authors: Mort J. , Chen I. , Grammatica S. , Morgan M.
Published: February 2003

Experimental and theoretical results are presented which suggest a unified picture of photogeneration processes in amorphous selenium and hydrogenated amorphous silicon. The different wavelength dependent quantum efficiency of photogeneration in these technologically important materials can be explained by a geminate recombination model if account is taken of their different dielectric constants.
Molecular beam epitaxy of AlSb
Authors: Chang Chin-An , Takaoka H. , Chang L. L. , Esaki L.
Published: February 2003

AlSb has been grown on (100)GaAs and GaSb by molecular beam epitaxy with good surface finish. High energy electron diffraction study reveals different interface morphologies between AlSb and GaAs, GaSb or InAs. Smooth interfaces are observed for AlSb-GaSb and AlSb-InAs while an initial stage of three-dimensional growth is observed for the AlSb-GaAs interface. Ge doping gives p-type AlSb in the range of ∼1014–1019 cm−3 under normal growth conditions.
Thermal regrowth of silicon(111) surface during ion bombardment
Authors: Yu Ming L.
Published: February 2003

The epitaxial regrowth of Si(111) surface damaged by low energy Ne+ bombardment was studied with low energy electron diffraction. The temperature for regrowth was consistently found to be lower when annealing was done during rather than after the ion bombardment. This is in line with the observation that crystalline Si films can be grown from the vapor at relatively low temperatures in a plasma or with ion beam processes.
Rapid degradation of InGaAsP/InP double heterostructure lasers due to 〈110〉 dark line defect formation
Authors: Endo K. , Matsumoto S. , Kawano H. , Sakuma I. , Kamejima T.
Published: February 2003

Rapid degradation has been observed for InGaAsP/InP double heterostructure lasers. It has been found that the rapid degradation is due to 〈110〉 dark line defects generated parallel to the stripe and its occurrence depends on the thickness of the InGaAsP contact layer. It has been shown that formation of a InGaAsP contact layer of more than 0.5-μm thickness is necessary in order to realize high reliability of the lasers.
Properties of an optically pumped far-infrared rooftop resonator: Output stability and eigenpolarizations
Authors: Mansfield D. K. , Jones K. , Semet A. , Johnson L. C.
Published: February 2003

A far-infrared dielectric waveguide laser has been decoupled from the pump laser by the use of rooftop mirrors as the cavity reflection elements. A concomitant increase in the pump and far- infrared output stability has resulted. Further, a new type of polarization behavior has been observed; the far-infrared output is circularly polarized with opposite helicities above and below line center. This behavior is independent of both the pump polarization and the molecular selection rules of the particular line in question.
Improvements on the electrical resistivity of chemical bath deposited CdS films by laser annealing
Authors: Martínez G. , Martínez J. L. , Zehe A.
Published: February 2003

The dark resistivity of cw Ar+ ion laser annealed chemical bath deposited CdS films has been measured. A two-decade decrement of the electrical resistivity, as compared to the unannealed samples, is reported. A threshold laser power density for reproducible annealing has been found to be ≳50 W/cm2. Log ρ vs 1/T plots were used to calculate the mobility ratio b = μn/μp. This ratio shows a slight increment on laser annealed but it is not sufficient to explain the resistivity changes.
A nematic liquid crystal storage display based on bistable boundary layer configurations
Authors: Cheng J. , Thurston R. N. , Boyd G. D. , Meyer R. B.
Published: February 2003

We describe a new twisted nematic liquid crystal display effect exhibiting bistable equilibrium states under an applied field. Each state is characterized by a boundary layer configuration whose properties provide for optical differentiation of the states. The basic principles, optics, and switching properties of this device are discussed.
VHF/UHF frequency measurement using the surface acoustic wave delay difference device
Authors: Ward Robert B.
Published: February 2003

A recently developed method for precise phase measurement of vhf/uhf signals has been used in frequency measurement system. Results are given from three test cases, two broadband (10 and 20 MHz) and one narrowband (300 kHz). In each case the frequency was measured with a precision which was a small fraction of the bandwidth and in the best case was 0.07% of the bandwidth. The configuration tested produced a reading every six milliseconds but a much higher rate is possible.
A simplified approach to computations of photoacoustic signals in gas-filled cells
Authors: Kuo P. K. , Favro L. D.
Published: February 2003

A relationship is derived between photoacoustic signals from localized sources and temperature distributions from extended sources. The result is applied to simple geometries.
A novel analytical design method for discharge laser electrode profiles
Authors: Stappaerts E. A.
Published: February 2003

An exact solution of the two-dimensional free-space Poisson equation for a discharge geometry is derived. It allows the calculation of electrode profiles starting from any assumed field distribution in the discharge midplane. Analytic expressions are obtained for a new class of profiles, and their properties are illustrated with the example of an XeCl laser discharge. The new profiles provide excellent field uniformity, and they are much more compact than other analytical profiles such as those of Rogowski and Chang.
Polarized infrared transmittance of carbon black-polyvinylchloride composite
Authors: Balberg I. , Zanzucchi P. J.
Published: February 2003

Resistivity measurement on carbon black-polyvinylchloride (PVC) composites combined with Monte Carlo calculations on the percolation threshold of a two-dimensional system of oriented sticks has suggested that the carbon black aggregates in these compression molded composites are oriented. Although electron microscopy failed to disclose structure in the composite, polarized infrared transmittance measurements do provide direct evidence for the orientation of carbon black aggregates. The degree of orientation from optical polarization correlates with orientation suggested by the resistivity measurements.
Thermally stimulated currents from positively corona-charged polypropylene films
Authors: Baba Atsushi , Ikezaki Kazuo
Published: February 2003

Thermally stimulated currents from positively corona-charged polypropylene films which were heat treated at various temperatures have been studied in the temperature range 20–165 °C. Three peaks are observed in the TSC spectra. Intensities of these peaks strongly depend on the thermal history of the sample films. A thermal effect of the TSC, which has been introduced during vacuum deposition of metallic electrodes on the sample films, is demonstrated. Observed results suggest that the electrical trap properties in polypropylene depend on the fine structure of the polymer.
Low-temperature growth of polycrystalline Si and Ge films by ultraviolet laser photodissociation of silane and germane
Authors: Andreatta R. W. , Abele C. C. , Osmundsen J. F. , Eden J. G. , Lubben D. , Greene J. E.
Published: February 2003

Polycrystalline Si and Ge films have been grown on amorphous SiO2 substrates (average Tsubstrate <120 °C) by the photodissociation of SiH4/N2 or GeH4/He mixtures, respectively, using pulsed ArF (193 nm) and KrF (248 nm) excimer lasers. For both Si and Ge, the film growth rate exhibited a strong dependence on laser wavelength and beam intensity I, where 1≲I⩽20 MW cm−2. As-deposited films exhibited average grain sizes of up to 0.5 μm and the grains were equiaxed with a random orientation. Ge films doped with ∼1020 cm−3 Al were obtained by the simultaneous photodissociation of Al(CH3)3 and GeH4.
Picosecond laser interaction with metallic zirconium
Authors: Yen R. , Liu J. M. , Bloembergen N. , Yee T. K. , Fujimoto J. G. , Salour M. M.
Published: February 2003

UV laser pulses of two picosecond duration have been used to observe photoelectric emission and thermally enhanced photoelectric emission from a zirconium metal surface. The data show that the electron and lattice temperature remain approximately equal and the electron-phonon energy relaxation time is less than 1 ps.
Monolithic integrated microgratings and photodiodes for wavelength demultiplexing
Authors: Suhara T. , Handa Y. , Nishihara H. , Koyama J.
Published: February 2003

The monolithic integration of micrograting filters and a photodetector array on a silicon substrate for optical wavelength demultiplexing is demonstrated. The demultiplexer is constructed with a series of micrograting filters fabricated by the electron beam direct writing technique in a chalcogenide (amorphous As2S3) film waveguide on a thermally oxidized silicon substrate and a Schottky barrier photodiode array fabricated on the Si surface.The device has the advantages of a high degree of design flexibility, high efficiency, low crosstalk, and very small dimensions. The design considerations and the fabrication process are described and the experimental results are discussed on the demultiplexing characteristics.
Inverse Zeeman scanning for the measurement of emission line profile in far ultraviolet region
Authors: Koizumi Hideaki , Oishi Konosuke , Yasuda Kazuo
Published: February 2003

We developed a new technique to observe the profiles of resonance emission lines in UV and VUV regions with a simple apparatus. The radiation from a source passed through an absorption cell placed in a gap of an electromagnet. The wavelength of the absorption line was shifted by means of the inverse Zeeman effect. The emission line profiles were obtained by measuring the absorbance as a function of the magnetic field strength. The emission line profiles and significant self-reversals were observed for Zn and Cd primary resonance lines at 213.9 and 228.8 nm, respectively.
Role of thermal diffusion in the redistribution of Cu during pulsed laser irradiating of Cu-implanted Al
Authors: Miotello A. , Donà dalle Rose L. F. , Desalvo A.
Published: February 2003

The inward diffusion of ion implanted Cu in Al during a nanosecond laser pulse is interpreted both as thermal and ordinary diffusion. Soret coefficients which reproduce the evolution of the implanted impurity profile as a function of the laser pulse parameters are obtained. These values are compared with the rather limited data available on thermal diffusion.
Electron mobilities in modulation doped Ga0.47In0.53As/Al0.48In0.52 As heterojunctions grown by molecular beam epitaxy
Authors: Cheng K. Y. , Cho A. Y. , Drummond T. J. , Morkoç H.
Published: February 2003

Modulation doped Ga0.47In0.53As-Al0.48In0.52 As single-period heterostructures have been prepared by molecular beam epitaxy (MBE). Electron mobilities as high as 8915 cm2/V s at 300 K, 60 120 cm2/V s at 77 K, and 90 420 cm2/V s at 10 K were obtained with an average electron concentration of ∼1017 cm−3. These results represent a mobility enhancement over uniformly doped Ga0.47In0.53 As with the same carrier concentration by about a factor of 6 at 77 K and by a factor of 2 at 300 K. Single-period modulation doped heterostructures have shown enhanced mobility in spite of the relative positions of the Si-doped Al0.48In0.52 As layer and the undoped Ga0.47In0.53 As layer in contrast to the case of GaAs/AlxGa1−x As system where mobility enhancement has only been observed for MBE grown AlxGa1−x As on top of the undoped GaAs layer.
Observation of coherent Cerenkov radiation at optical frequencies
Authors: Kimura W. D. , Wang D. Y. , Piestrup M. A. , Fauchet A. M. , Edighoffer J. A. , Pantell R. H.
Published: February 2003

Coherent Cerenkov radiation at 0.532 μm was observed from an optically bunched relativistic electron beam. Bunching was induced by means of the inverse Cerenkov effect wherein, to achieve phase matching, light at 1.06 μm from a Nd:YAG laser intersected the electron beam at the Cerenkov angle within a gaseous medium. The pressure dependence of this radiation was verified.
Selective excitation luminescence in bulk-grown GaAs
Authors: Hunter A. T. , McGill T. C.
Published: February 2003

We have measured the excited state levels of two different shallow acceptors in bulk-grown GaAs, using selective excitation luminescence. The 1S–2S energy differences were measured to be 21.5 and 18.5 meV, respectively. By comparing these values to those measured by two-hole transition luminescence in high quality epitaxial GaAs [Ashen et al., J. Phys. Chem. Solids 36, 1041 (1975)], the acceptors were identified as Zn and C. The measured 1S–2P energy differences also support the identification. These studies demonstrate that selective excitation luminescence can be used to identify shallow acceptors in bulk-grown semi-insulating GaAs, and hence can be used as a diagnostic tool for bulk-grown samples.
Effects of thermal annealing on the refractive index of amorphous silicon produced by ion implantation
Authors: Fredrickson J. E. , Waddell C. N. , Spitzer W. G. , Hubler G. K.
Published: February 2003

Precise infrared reflection measurements of the refractive index of silicon show that there are two well-defined optical states of amorphous silicon produced by ion implantation. One is the as-implanted amorphous state which is the high refractive index state produced by high fluence implantation of Si or P ions into Si samples. The other state, which has a refractive index intermediate between the as-implanted and crystalline values, is induced by thermal annealing and is thermally stable until epitaxial recrystallization occurs.
Investigation of impurity variations by cathodoluminescence imaging: Application to GaSb:Te
Authors: Chin A. K. , Bonner W. A.
Published: February 2003

Crystals grown by the Czochralski technique frequently exhibit periodic variations of impurity concentration. These growth striations are microscopic in size and provide detailed information on the growth conditions. Although these striations are easily revealed by chemical etching, quantitative changes in carrier concentration are not easily determined. In this letter, the cathodoluminescence (CL), efficiency of GaSb:Te crystals is presented as a function of carrier concentration. The periodic variations in CL intensity, spatially correlated with growth striations revealed by an etchant, corresponds to ∼20% changes in carrier concentration. Finally, within the resolution of the CL technique, no evidence of a second phase is found in GaSb crystals doped with Te to the solubility limit.
High-efficiency, low-threshold, Zn-diffused narrow stripe GaAs/GaAlAs double heterostructure lasers grown by metalorganic chemical vapor deposition
Authors: Hong C. S. , Coleman J. J. , Dapkus P. D. , Liu Y. Z.
Published: February 2003

Deep Zn-diffused, 4-μm stripe thin p active layer GaAs/GaAlAs double heterostructure lasers grown by metalorganic chemical vapor deposition are reported. Threshold currents as low as 40 mA (length 220 μm), a characteristic temperature as large as 170 °C, and external differential quantum efficiencies as high as 80–90% are obtained. Single longitudinal and transverse mode operation of these lasers is also observed.
Fresnel reflection and transmission at a planar boundary from media of equal refractive indices
Authors: Giles C. Lee , Wild Walter J.
Published: February 2003

Some interesting properties of the Fresnel equations governing the reflection of plane electromagnetic waves at an interface between differing media are presented. The phenomenon of reflection that is independent of angle of incidence is shown to be theoretically possible if the media possess different magnetic permeabilities.
Transient frequency and temperature variation of GaInPAs lasers under pulsed excitation
Authors: Ito Ryoichi , Suyama Masuo , Ogasawara Nagaatsu
Published: February 2003

Transient frequency and temperature variation of GaInPAs buried heterostructure lasers have been measured by means of a Michelson interferometer. It is demonstrated that the thermal resistance, the heat generation rate in the active layer, and the internal quantum efficiency can be deduced by this method. The dependence of the laser frequency on current is also estimated.
Low energy electron impact attachment and ionization in HgBr2
Authors: Wiegand W. J. , Boedeker L. R.
Published: February 2003

Cross sections for low energy electron impact attachment and ionization in mercuric bromide (HgBr2) have been measured using an electron beam experiment. The ion products of these reactions, as identified by mass analysis, are Br− and chiefly HgBr+2. Rate coefficients computed from the measured cross sections were found to be in good agreement with values determined independently from an electron swarm experiment.
The annealing behavior of antimony implanted polycrystalline silicon
Authors: Tandon J. L. , Harrison H. B. , Neoh C. L. , Short K. T. , Williams J. S.
Published: February 2003

Dopant redistribution and sheet resistance of polycrystalline silicon films implanted with 100-keV Sb+ ions to a dose of 1×1015 cm−2 or 3×1015 cm−2 have been investigated as a function of different annealing conditions. The correlation between Sb depth profiles, as measured by Rutherford backscattering, and sheet resistance provides considerable insight into the Sb doping behavior. In particular, low-temperature (∼600 °C) short-time (0.5 h) anneals resulted in good dopant activation without redistribution of the implanted Sb, whereas higher-temperature anneals (≳900 °C) resulted in considerable redistribution. The sheet resistance of the films appeared to be controlled, to a large extent, by dopant segregation at grain boundaries and the fraction of the redistributed Sb within the grains.
Multiple-trapping dispersive transport at high temperatures
Authors: Silver M. , Cohen Leon , Adler David
Published: February 2003

We discuss the results of a computer simulation of dispersive transport from an exponential distribution of traps in the high-temperature regime in which kT is of the order of the width of the trapping levels. We find that the mobility still decreases with time, although the relationship is not so simple as at low temperatures. The results are applied to a-Si:H alloys. We conclude that the mobility of electrons beyond the conduction band mobility edge is larger than 10 cm2/V s in these alloys.
Low-temperature coefficient bulk acoustic wave composite resonators
Authors: Wang J. S. , Lakin K. M.
Published: February 2003

This letter reports on an acoustic bulk wave resonator structure having an absolute temperature coefficient of series or parallel resonant frequency of less than 4 ppm/°C over the temperature range −20 to +120 °C comparing favorably with that of conventional AT cut quartz. In addition, the resonant Q was 7600 for parallel and 7300 for series resonance at frequencies near 330 MHz for the fundamental mode. The resonator is composed of a unique composition of an AlN piezoelectric film sputtered on a single-crystal silicon membrane for a total thickness of less than 10 μ. The resonator coupling coefficient was found to be 2.5% corresponding to film coupling of 12%. The AlN films were prepared in a dc planar magnetron reactive sputtering system.
Photoacoustic pulse generation and probe-beam deflection for ultrasonic velocity measurements in liquids
Authors: Zapka W. , Tam A. C.
Published: February 2003

We have demonstrated a noncontact, fast, and accurate method for ultrasonic measurements in liquids. A pulse laser beam produces an acoustic pulse, whose propagation is monitored by its deflection effects on two cw probe beams. All laser beams are parallel to, but displaced from, one another. The acoustic velocity can be measured to an accuracy of 5 parts in 104 in a measurement time of 100 μs. Temperature-dependent velocities are measured for ethanol, methanol, water, as well as for concentrated sulfuric acid (which has not been measured previously).
Microstrain in laser-crystallized silicon islands on fused silica
Authors: Lyon S. A. , Nemanich R. J. , Johnson N. M. , Biegelsen D. K.
Published: February 2003

Residual strain in cw laser-crystallized silicon thin films has been measured with high spatial resolution (∼5 μm) by Raman spectroscopy. Thin films of polycrystalline silicon were defined into moated islands and patterned stripes on fused silica substrates and encapsulated with silicon nitride. Raman scattering was used to measure local strain at various points in and near crystallized islands, and the results reveal that the silicon film is under tension. The observations indicate that a major component of the stress in the film arises from pinning of the silicon at the silicon-fused silica interface at the solidification temperature followed by differential thermal contraction.
Self-pulsing and chaos in distributed feedback bistable optical devices
Authors: Winful Herbert G. , Cooperman Gene D.
Published: February 2003

We show that the light transmitted by a nonlinear distributed feedback structure can be steady (time independent), periodic, or chaotic depending on the intensity of the input cw beam. The feasibility of an experimental demonstration of such behavior is discussed.
High-efficiency electrodeposited cadmium telluride solar cells
Authors: Fulop G. , Doty M. , Meyers P. , Betz J. , Liu C. H.
Published: February 2003

We report on the development of a low-cost, thin-film electrodeposited cadmium telluride solar cell. The most efficient cell developed to date had an efficiency of 8.6% (under AM1 illumination), an open circuit voltage of 0.723 V, a short circuit current density of 18.7 mA/cm2, and a fill factor of 0.64. The cell uses a Schottky barrier rectifying junction at the front surface and a cadmium ohmic contact at the back. Passivation of the top surface improves the photovoltaic properties of the rectifying junction.
Single phase polycrystalline metastable (GaSb)1−xGex alloys from annealing of amorphous mixtures: Ion mixing effects during deposition
Authors: Cadien K. C. , Greene J. E.
Published: February 2003

Low energy (<100 eV) Ar+ ion bombardment of the growing film during the deposition of amorphous GaSb+Ge mixtures was found to affect both the transformation rate kinetics as well as the reaction path during subsequent annealing. Ion bombardment induced collisional cascades resulted in more random mixing in the growing films thus retarding the rate of the amorphous to equilibrium state phase transformation during annealing and allowing the formation of homogeneous metastable randomly oriented single phase (GaSb)1−xGex alloys. The films were ∼1.5 μm thick and the average grain size in the metastable state was ∼300 Å.
Multiply scanned electron beam annealing of Si implanted GaAs
Authors: Bujatti M. , Cetronio A. , Nipoti R. , Olzi E.
Published: February 2003

Low dose implants of Si into semi-insulating GaAs have been annealed by multiply scanned electron beam yielding 100% activation, without the compensation threshold characteristic of thermal annealing, and a high drift mobility of 4100 cm2/Vs for a carrier concentration of 1.6×1017 cm−3. Secondary-ion mass spectroscopy analysis has revealed that the formation of a trough, depleted of Cr in correspondence with the implanted Si, is responsible for these results.
Refractive index of vinylidene fluoride-trifluoroethylene copolymer
Authors: Yamada Takeshi , Kurokawa Takashi
Published: February 2003

The refractive indices of the ferroelectric vinylidene fluoride-trifluoroethylene copolymer have been investigated. The copolymer reveals birefringence in all its composition ranges. Birefringence of the copolymer film is observed even at higher temperatures than the Curie temperature. The noticeable decrease of the refractive indices at around the Curie temperature is caused by a change of the density.
Visible GaAlAs V-channeled substrate inner stripe laser with stabilized mode using p-GaAs substrate
Authors: Yamamoto S. , Hayashi H. , Yano S. , Sakurai T. , Hijikata T.
Published: February 2003

A new visible laser, the V channeled substrate inner stripe laser, is developed. This laser can internally confine the current into the V-channel by using a thin n-GaAs layer grown on the p-GaAs substrate. cw threshold currents were 35–45 mA in the visible spectral range of 770–790 nm. And highly stable transverse and single longitudinal mode operation were observed because the built-in optical waveguide was formed within the V channel.
Subgrain boundaries in laterally seeded silicon-on-oxide formed by graphite strip heater recrystallization
Authors: Pinizzotto R. F. , Lam H. W. , Vaandrager B. L.
Published: February 2003

A detailed microstructural analysis of laterally seeded silicon-on-oxide formed by scanning graphite strip heater recrystallization is presented for the first time. The recrystallized top silicon layer has a (100) orientation, but contains many subgrain boundaries formed by dislocation coalescence. The subgrains are misoriented by <0.3° and have no internal defects. β-SiC contamination of the top silicon layer was detected. It is probably due to particulate contamination from the top graphite strip heater.
Measurement of the Γ-L separation in Ga0.47In0.53As by ultraviolet photoemission
Authors: Cheng K. Y. , Cho A. Y. , Christman S. B. , Pearsall T. P. , Rowe J. E.
Published: February 2003

We have studied the valence band of Ga0.47In0.53As by ultraviolet photoemission using photon energies of 11.7, 16.8, and 21.2 eV. The photo-electron energy spectra show that the valence band of Ga0.47In0.53As has well-defined structure similar to that of binary III-V semiconductors. We have used these spectra to determine a conduction band Γ-L separation of 0.55 eV at 300 K.
Radiometric levitation of micron sized spheres
Authors: Lewittes M. , Arnold S. , Oster G.
Published: February 2003

Radiometric levitation of a 20-μ-diam dye-impregnated glycerol sphere has been observed at intensities as low as ∼1 W/cm2 in air at 30 Torr. The levitation has been effected on both strongly absorbing spheres in the direction of the light and weakly absorbing spheres in the opposite sense. Both strongly and weakly absorbing spheres are found to laterally seek an intensity minimum. Consequently particles were stably held in the focused beam of an Ar+ laser (4880 Å) operating in the TEM*01 (doughnut) mode.
Shock dynamics and neutron production in an explosive generator driven dense plasma focus
Authors: Lindemuth Irvin R. , Freeman Bruce L.
Published: February 2003

An explosive generator driven dense plasma focus is simulated numerically using a magnetohydrodynamic model which includes thermal conduction, resistive diffusion, and radiation in addition to the Lorentz force and shock hydrodynamics. It is shown that the dominant heating mechanism is shock heating. Neutron yield is shown to occur at the current minimum. The neutron yield is a result of the initial shock reflecting off the axis of symmetry, reflecting off the magnetic piston driving the focus, and reconverging on axis. Peak neutron production occurs when post-shock plasma converges on axis.
Fermi level pinning at metal-CdTe interfaces
Authors: Williams R. H. , Patterson M. H.
Published: February 2003

Schottky barrier formation has been studied for a range of metals on vacuum cleaved CdTe surfaces, using a multi technique approach. Provided one eliminates the situation of cadmium outdiffusion into high work function metals from the analysis, then the data are far closer to the Schottky limit than previously reported. The influence of defects is discussed in the light of recent data relating to Au-Cd alloy contacts.
Characterization of high purity GaAs grown by molecular beam epitaxy
Authors: Dingle R. , Weisbuch C. , Störmer H. L. , Morkoç H. , Cho A. Y.
Published: February 2003

High purity n-type GaAs grown by molecular beam epitaxy has been characterized using the Hall effect, dye laser excited low-temperature luminescence, and far-infrared magnetospectroscopy. Peak mobilities exceed 105 cm2 V−1 s−1. Carbon is shown to be the dominant background acceptor impurity, whereas silicon and two additional, unidentified donors make up the background donor manifold.
GaAs/AlxGa1−xAs depletion stop phototransistor grown by molecular beam epitaxy
Authors: Chen C. Y. , Cho A. Y. , Garbinski P. A. , Bethea C. G.
Published: February 2003

We introduce a simple but useful concept of depletion stop and demonstrate a phototransistor that makes use of this idea. This depletion stop phototransistor is grown by molecular beam epitaxy on GaAs substrates. The base region is composed of a lightly doped layer near the emitter junction and a heavily doped layer near the collector junction. The edge of the depletion region at the emitter junction is designed to stop at the lightly doped base. A dc optical gain ≳10 has been successfully observed. Further applications of this idea to the fabrication of a depletion stop double emitter double base transistor and to the Si-based devices are also discussed.
Amorphous silicon p-i-n solar cells fabricated by reactive sputtering
Authors: Moustakas T. D. , Friedman R.
Published: February 2003

We report, for the first time, the fabrication of indium-tin-oxide p-i-n amorphous silicon solar cells by the method of reactive sputtering. These solar cells exhibit power conversion efficiency of 4.0% under AM1 illumination. The junction characteristics of these solar cells are discussed.
Ion implantation of Be in In0.53Ga0.47As
Authors: Tabatabaie-Alavi K. , Choudhury A. N. M. M. , Slater N. J. , Fonstad C. G.
Published: February 2003

Multiple energy Be+ ion implantation has been used to produce p-type regions in n-In0.53Ga0.47As (n≃1016 cm−3). A simple technique has been developed for capless annealing of InGaAs up to 700 °C. The activation efficiency of the implanted Be+ is dependent on the implant energy and dosage with a maximum activation of 40% for 50-keV implants. When the total implant dose exceeds 1014 cm−2, substantial diffusion of Be occurs resulting in a p+-n−-n structure. Planar diodes formed by Be+ implantation have a reverse breakdown voltage of 50 V and an ideality factor of 1.5 in the forward direction.
Band tail recombination limit to the output voltage of amorphous silicon solar cells
Authors: Tiedje T.
Published: February 2003

Recombination mediated by band tail states is shown to substantially reduce the maximum achievable output voltage in amorphous silicon hydride solar cells. The maximum open circuit voltage calculated from measured density of states parameters and reasonable estimates for the localized state capture rates is 1.0±0.1 V.
Electrochemical diffusion of arsenic in silicon through thermal thin SiO2 films
Authors: Martinez J. L. , Ruiz J. C.
Published: February 2003

In this letter we report experimental results of electrochemical doping of 〈111〉 p-type silicon with arsenic through thin SiO2 films. C-V plots of metal-oxide-semiconductor n-p junctions, made in the electrochemical process, were taken. Data of the amount of arsenic impurity concentration diffused into silicon are given for different electrochemical diffusion times. An estimate value for the diffusion coefficient of arsenic in SiO2 films at room temperature is also presented.
Planarization of patterned surfaces by ion beam erosion
Authors: Johnson L. F. , Ingersoll K. A. , Kahng D.
Published: February 2003

The angular dependence of ion beam erosion has been utilized to achieve planarization of patterned surfaces. Deviation from planarity of <500 Å has been demonstrated on planarized SiO2 covered patterned Si surfaces with 1.5-μm-deep recesses. The technique should be applicable to a wide variety of materials with different physical, chemical, optical, and electrical properties, and should be particularly useful in very high speed integrated circuit development.
Single-mode integrated optical 1×N star coupler
Authors: Findakly T. , Chen B.
Published: February 2003

A new 1×N single-mode integrated optical star coupler is presented. Directional couplers with linearly changing spacing are utilized to optimize various loss aspects. The device is fabricated on glass substrates by Na+↔K+ ion exchange.
4-bit 828-megasample/s electro-optic guided-wave analog-to-digital converter
Authors: Leonberger F. J. , Woodward C. E. , Becker R. A.
Published: February 2003

Individual bit channels of a 4-bit guided-wave electro-optic analog-to-digital converter have been demonstrated at 276 and 828 megasamples per second. The converter consists of a mode-locked Nd: yttrium aluminum garnet (YAG) laser for sampling, a LiNbO3 Ti-indiffused waveguide interferometric modulator array for conversion, a Ge avalanche photodiode (APD), and a special 1-GHz Si integrated circuit for digital processing. Beat-frequency tests with a 413-MHz test signal, representing the highest frequency analog waveform converted, are reported.
A laser deflection technique for sensitive measurements of a reduced-density channel in neutral gas
Authors: Greenspan M. A. , Reddy K. V.
Published: February 2003

The radial profile of neutral gas density has been measured for a reduced-density channel in 2.7-kPa (20 Torr) air produced by an electrical discharge. Deflection by the channel of a He-Ne laser is measured by a sensitive position detector, and the density profile is unfolded using an Abel inversion. Density changes of ∼1017/cm3 in air can be measured by this means.
Oxygen precipitation effects on Si n+-p junction leakage behavior
Authors: Chakravarti S. N. , Garbarino P. L. , Murty K.
Published: February 2003

The effects of oxygen precipitation in (100) Si wafers on junction leakage characteristics are investigated for double polysilicon gate field-effect transistor dynamic random-access memory technology. Experimental data indicate the presence of a very large bulk diffusion leakage current component in the elevated (≳45 °C) temperature range. A simple one-dimensional minority-carrier diffusion model predicts the existence of carrier generation centers at the interface between the precipitate-free and the precipitated regions in the bulk.
Electron and hole impact ionization coefficients in InP determined by photomultiplication measurements
Authors: Cook L. W. , Bulman G. E. , Stillman G. E.
Published: February 2003

The electron and hole ionization coefficients α and β in (100) InP have been determined through analysis of photomultiplication data on p+-n and n+-p junctions grown by liquid phase epitaxy (LPE). A special device structure is described which allows reproducible thinning of the substrate in order to achieve pure carrier injection from either side of the p-n junction. By fabricating wafers with depletion layer doping levels from 1.2×1015 to 1.2×1017 cm−3, α and β have been determined over a wider range of electric fields than previously reported. The ratio of β/α decreases from 4.0 to 1.3 as the electric field is increased from 2.4 to 7.7×105 V/cm.
Optoelectronic picosecond sampling system utilizing a modulated barrier photodiode
Authors: Bethea C. G. , Chen C. Y. , Cho A. Y. , Garbinski P. A.
Published: February 2003

We describe an opto-electronic picosecond sampling system utilizing the newly developed modulated barrier majority-carrier photodetectors. By synchronously detecting amplitude modulated trains of optical picosecond pulses, the high-speed response of n-type majority-carrier devices has been measured.