bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial mode discrimination and control in high-power single-mode constricted double-heterojunction large-optical-cavity diode lasers
Authors: Butler J. K. , Botez D.
Published: February 2003

Mode discrimination and control in high-power constricted double-heterojunction large-optical-cavity (CDH-LOC) lasers are determined by three factors: a sharp lateral variation in radiation confinement factor, a ‘‘built-in’’ dielectric W guide in the plane of the junction, and the influence of gain-induced index depressions on the W guide. Excellent far-field pattern fits are achieved by using the actual geometries and compositions of two high-power CDH-LOC structures, and gain-induced (bulk) index depressions in the −0.02 to −0.03 range. The dependence of mode discrimination on the gain-induced index depression allows tailoring CDH-LOC devices for specific spatial mode operation.
High conductivity zinc sulfoselenide thin films
Authors: Leigh Wallace , Wessels Bruce W.
Published: February 2003

High conductivity thin films of ZnSSe have been deposited using hydrogen vapor transport. The films grown on GaAs are single crystalline and have excellent surface morphologies. Resistivities of the as-grown material ranged from 1 to greater than 103 Ω cm depending upon zinc partial pressure of the growth ambient and sulphur concentration in the film. For a film with a composition of ZnS0.12Se0.88 , a carrier concentration of n = 5×1016 cm−3 and mobility of 126 cm2/Vs were observed.
Vibrational excitation of HCl in electron beam excited Ar/HCl mixtures
Authors: Center R. E. , Jacob J. H. , Rokni M. , Rozenberg Z.
Published: February 2003

Measurements have been made of the vibrational excitation of HCl under typical e-beam XeCl laser conditions. The results indicate less than 10% excitation to the first vibrational level. This is too small to yield the tenfold enhancement of dissociative electron attachment predicted by existing XeCl laser models.
In0.53Ga0.47As n-channel native oxide inversion mode field-effect transistor
Authors: Liao A. S. H. , Tell B. , Leheny R. F. , Chang T. Y.
Published: February 2003

We describe a native oxide insulated gate, inversion mode In0.53Ga0.47As field-effect transistor. Drain characteristics measured with pulsed gate voltage yield gm of 33 mS/mm and an effective saturated drift velocity for inversion layer electrons of 2.6×106 cm/s. The presence of a slow drift in drain current is found to reduce the transconductance to 20 mS/mm for low-frequency measurements.
Iron nitride and carbonitride phases in a nitrogen implanted carbon steel
Authors: dos Santos C. A. , de Barros B. A. S. , de Souza J. P. , Baumvol I. J. R.
Published: February 2003

Iron nitride and carbonitride phases formed during nitrogen implantation and subsequent thermal annealing of a medium-carbon steel are investigated by means of conversion electron Mössbauer scattering. The results are compared to previous work on similar systems and also discussed in terms of the mechanical properties of ion implanted steels.
Self-injected neodymium-yttrium aluminum garnet laser with an unstable cavity
Authors: Palange E. , Brito Cruz C. H. , Di Lazzaro P. , De Martini F.
Published: February 2003

The first ’’self-injected’’ unstable resonator laser is reported. 1-ns, high peak power, single-mode pulses are generated with neodymium-yttrium aluminum garnet (Nd-YAG) laser made with the same relevant optical components of the commercial DCR1 Quanta Ray oscillator.
Thermal-gradient-induced optical deflection in TiO2 crystals
Authors: Fujii Y. , Kajimura K. , Ishihara S. , Yajima H.
Published: February 2003

A physical interpretation of the novel optical deflection phenomenon is reported with detailed measurements on rutile (TiO2) crystals under both static and pulse electric fields. With a model based on the thermally induced refractive index gradient, the experimental results of deflection angles are successfully explained.
Solid phase epitaxial recrystallization of thin polysilicon films amorphized by silicon ion implantation
Authors: Kwizera P. , Reif R.
Published: February 2003

Thin polycrystalline silicon films have been amorphized by silicon ion implantation and subsequently annealed at 525 °C for various lengths of time. Due to channeling of the ion beam through properly oriented polycrystalline grains, a few grains survived the implantation step and acted as seeds for solid phase epitaxial recrystallization of the film. This technique makes it possible to increase the grain size of thin polycrystalline films at very low temperatures.
Efficient cadmium sulfide on silicon solar cells
Authors: Arya R. R. , Sarro P. M. , Loferski J. J.
Published: February 2003

p-Si/CdS heterojunction solar cells, fabricated by single source evaporation of CdS over silicon at low temperatures (∼175 °C), which have solar power conversion efficiencies up to 11%, measured under simulated AM1 illumination, are described.
Internal loss of InGaAsP/InP buried crescent (λ = 1.3 μm) laser
Authors: Higuchi Hideyo , Namizaki Hirofumi , Oomura Etsuji , Hirano Ryoichi , Sakakibara Yasushi , Susaki Wataru , Fujikawa Kyoichiro
Published: February 2003

The temperature dependence of the internal loss α of the InGaAsP/InP buried crescent laser is presented in the temperature range 20–80 °C. α is about 18 cm−1, and no apparent temperature dependence of α is observed in this temperature range. This indicates that the temperature-sensitive behavior of the threshold current in InGaAsP/InP long-wavelength lasers is not due to the temperature dependence of internal loss. The decrease in the external quantum efficiency with increasing temperature is attributed to the decrease in the internal quantum efficiency.
Large amplitude wave packets of ionization waves
Authors: Ohe Kazuyuki
Published: February 2003

The temporal and spatial growth rates of large amplitude ionization waves are measured from the evolutions of the wave packets. The group velocity has a constant value for the small amplitudes, while it increases proportionally to the square of wave amplitude for the large amplitudes. The phase velocity at the front of the carrier wave has a similar wave amplitude dependence to that of the group velocity. The velocity at the tail decreases inversely proportionally to the wave amplitude. The increases of the group and phase velocities can be theoretically explained by the nonlinear frequency shift.
Contactless measurement of Schottky barrier heights using secondary electrons
Authors: Huang H.-C. W. , Ho P. S.
Published: February 2003

A contactless technique using electron-beam-induced voltage has been developed to measure the barrier heights of Schottky diodes. The method detects the change in the on-set energy of the secondary electrons using a cylindrical mirror analyzer in a scanning Auger microprobe (SAM). Measurements have been carried out in a Si diode with half-high-barrier (platinum) and half-low-barrier (titanium) height metal coverage in order to establish the correlation between the measured energy change to the difference in the barrier heights. Using an electron beam of about 1-μm diameter, a change in the on-set energy of 50 meV can be detected with a lateral resolution of about 1 μm. The fine-beam Auger capability of the SAM enables us to identify in situ the local chemistry change responsible for the barrier height variation. This provides a technique with high spatial and energy resolution for investigating the correlation between the interface chemistry and electrical properties of mixed diodes.
Electron paramagnetic resonance study of electric gun induced reactions in the solid state
Authors: Owens F. J.
Published: February 2003

A foil flyer plate electric gun device has been used to shock and recover potassium cyanate containing radiation induced paramagnetic molecules. The shock induced reaction of the molecules is monitored as a function of peak shock pressure by electron paramagnetic resonance of the recovered samples.
Time correlations of electron and positive ion emission accompanying and following fracture of a filled elastomer
Authors: Dickinson J. T. , Jensen L. C. , Park M. K.
Published: February 2003

When filled elastomers fracture intense electron emission (EE) and positive ion emission (PIE) accompany and follow crack propagation, two important components of what we call fracto-emission. We present here results of simultaneous measurements of EE and PIE from polybutadiene filled with glass beads. These measurements indicate that (a) the EE and PIE decay kinetics are identical, (b) substantial components of EE and PIE are emitted in coincidence, and (c) an excited neutral species is also emitted in coincidence with the EE.
High pressure measurements on visible spectrum AlxGa1−xAs heterostructure lasers: 7100–6750-Å 300-K operation
Authors: Kirchoefer S. W. , Meehan K. , Holonyak N. , Gulino D. A. , Drickamer H. G. , Burnham R. D. , Scifres D. R.
Published: February 2003

Pressure applied to high performance cw 300-K bulk-limit (Lz∼ 600 Å) single quantum well heterostructure AlxGa1−xAs (x∼0.28, λ∼7100 Å) laser diodes is used to simulate composition change and determine the threshold increase at shorter wavelength. Unless small quantum well sizes are employed in more sophisticated designs it is unlikely that λ (for cw 300-K operation) can be made much less than 6900 Å.
Ultrafast optoelectronic switching in Blumlein pulse generator
Authors: Chang C. S. , Mathur V. K. , Rhee M. J. , Lee Chi H.
Published: February 2003

Blumlein pulse generator has the potentiality of yielding pulse amplitude equal to the charging voltage. By applying the technique of optoelectronic switching to Blumlein pulse generator, square pulses with ultrafast rise time have been generated. In such cases, the rise time is essentially controlled by the temporal width of the picosecond laser pulse.
High peak power picosecond light pulses from a directly modulated semiconductor laser
Authors: Klein H.-J. , Bimberg D. , Beneking H. , Kuhl J. , Göbel E. O.
Published: February 2003

We report the generation of short light pulses of 23-ps duration from an unbiased proton implanted double heterostructure cw laser by direct gain modulation. Repetition frequencies up to 10 MHz and a typical peak power of 300 mW are achieved. The time behavior of the light output is largely independent of the rise and fall time of the modulation current, since the first relaxation oscillation of the laser is utilized.
Relative energy deposition of electrons in a magnetic guide field
Authors: McGeoch M. W.
Published: February 2003

The spatial dependence of electron beam deposition was measured for a 320-kV beam propagating into argon, guided by a magnetic field of 1 kG. Deposition was monitored using the HgBr (B-X) fluorescence at 502 nm, which is believed to arise from the recombination of HgBr+2.
High-gain air breathing electric discharge CO2 laser
Authors: Hara H. , Sugii M.
Published: February 2003

The small-signal gain and the output power of air breathing electric discharge CO2 laser have been measured in the absence of He gas. A maximum gain of 4.9 m−1 was observed at a gas composition of CO2:air = 120:80 (l/min, at normal state), and a 45-W output power was obtained with an energy conversion efficiency of 5.1%. The corresponding specific power was 7.4 J/g.
Current density and pressure dependence of XeCl excimer fluorescence and laser emissions observed in a very small volume discharge
Authors: Lou Qi-hong , He Qi-sheng , Lin Shao-Chi
Published: February 2003

Some observational results on the XeCl excimer B→X fluorescence and laser emissions from dilute Ne/Xe/HCl mixtures in a very small volume (∼1 cm3) pulsed avalanche discharge of ∼200-ns duration at high current densities (0.6< j<1.8 kA/cm2) and at high gas pressures (2< p<11 atm) are presented. With increasing  j, p, and Ne dilution, the fluorescence pulse duration becomes more and restricted but the laser peak power continues to show an upward trend until p≊8 atm. In spite of the short pulse and low extraction efficiency, laser peak power of up to ∼10 kW has been observed from the ∼1-cm3 volume discharge.
Improved performance of mini-repetitively pulsed CO2 lasers using H2 buffered gas mixtures
Authors: Dyer P. E. , Tait B. L.
Published: February 2003

The improved performance characteristics of a compact pulsed, atmospheric pressure CO2 laser using He-free, H2 buffered gas mistures are reported. Both peak and average power are found to be optimal with this mixture as a result of an enhanced gain amplitude and rise time. A ∼2.7-cm3 discharge has produced 17-W average laser power at ∼300 Hz.
Frequency tuning for stimulated four-photon mixing by bending-induced birefringence in a single-mode fiber
Authors: Kitayama Ken-ichi , Ohashi Masaharu
Published: February 2003

A new type of frequency tuning for stimulated four-photon mixing is demonstrated using bending-induced birefringence in a single-mode fiber. It is experimentally verified that the frequency shift of the Stokes emission is tuned by approximately 100 cm−1 via the bending-induced birefringence in the spectral region around 1 μm. This will provide a new application of a birefringent fiber to a optical frequency generator.
Silicon solar cell with a novel low-resistance emitter structure
Authors: Borden P. G. , Walsh R. V.
Published: February 2003

A silicon solar cell with over 19% efficiency at 100 suns, AM1.5, 20 °C, incorporating a novel front contact geometry, has been demonstrated. The cell has one third of its frontal area covered with metal and grid line spacing of 82 μ, as measured along the silicon surface. It uses V-groove etching, angle-contact metal evaporation, and a cover glass to allow high fractional grid coverage with low obscuration, thereby minimizing emitter resistance losses at high concentrations.
Epitaxial growth of Pd2Si films on Si(111) substrates by scanning electron-beam annealing
Authors: Ishiwara Hiroshi , Yamamoto Hiroshi
Published: February 2003

Pd2Si films were grown epitaxially onto Si(111) substrates by scanning electron-beam annealing of deposited Pd films. Single phase silicide formation and epitaxial growth were studied by Nomarski optical microscopy, x-ray diffraction analysis, and Rutherford backscattering and channeling techniques. The crystalline quality of the electron-beam-annealed Pd2Si films was weakly dependent on annealing conditions and somewhat worse than that of furnace-annealed films.
Far-infrared radiation from thin-film plasmons excited at the difference frequency of two CO2 lasers
Authors: McManus J. B.
Published: February 2003

We report the first observation of radiation from coherently excited thin-film plasmons of definite wave vector. With two noncollinear CO2 laser beams incident on a 20-μm-thick film of n-InSb, a difference frequency radiation at ∼100 cm−1 was generated, with a resonance at the plasma frequency. Previous theory had indicated than thin-film plasmons of definite wave vector could be coherently excited with a longitudinal driving force produced at the difference frequency of two laser beams. This thin-film plasmon is partially transverse and radiates efficiently. The observed difference frequency generation as a function of angle and difference frequency follows the theoretical predictions.
Thermal pulse annealing of boron-implanted HgCdTe
Authors: Conway K. L. , Opyd W. G. , Greiner M. E. , Gibbons J. F. , Sigmon T. W. , Bubulac L. O.
Published: February 2003

Crystal damage, caused by a 1015 11B/cm2 250-keV implant into epitaxial Hg0.64Cd0.36Te layers held at LN2 temperature, has been successfully annealed, as observed by MeV 4He ion channeling and Rutherford backscattering. The anneal consists of a thermal pulse of 250 °C for 8 s in air under a Si proximity cap. Secondary ion mass spectrometry (SIMS) data indicate that the boron did not diffuse during the anneal. An n-p junction was observed at a depth of 5.5 μm by electron beam induced current (EBIC) measurements. A diode fabricated on the layer exhibited a very sharp I-V curve with reverse breakdown occurring at 12 V and an R0A of ⩾107 Ω cm2 at 77 K.
Ring formation of Kirkendall voids in Pb-alloy thin-film diffusion couples
Authors: Huang H.-C. W.
Published: February 2003

Ring formation has been observed in thin-film diffusion couples consisting of a 400-nm-thick Pb0.71Bi0.29 (in weight fraction) or Pb layer above a 200-nm-thick Pb0.84In0.12Au0.04 layer with a very thin (∼6 nm) rf-grown oxide diffusion barrier in between. When interdiffusion was initiated by a rupture in the oxide barrier, concentric rings were observed to form in Pb-Bi or Pb layer centering at the rupture site as interdiffusion proceeded. Rings were found to be a string of voids resulting from Kirkendall interdiffusion. In addition, relatively high concentrations of indium and oxygen were found at rings. Although the mechanism for ring formation is not clear at present, factors which influence ring formation are discussed.
Magneto-optical detection of deep acceptor impurities in p-InSb
Authors: Littler C. L. , Seiler D. G. , Kaplan R. , Wagner R. J.
Published: February 2003

We report the first magneto-optical experiments on Au-doped p-InSb and show how they can be used to detect and identify impurities in semiconductor materials. A ground state binding energy of 42.5±0.5 meV has been determined for the lower level of the Au double acceptor in InSb. The technique also provides information about the magnetic field dependence of the excited states associated with a deep acceptor level.
Ablative hole formation process in thin tellurium and tellurium-alloy films
Authors: Chen M. , Marrello V. , Gerber U. G.
Published: February 2003

Static measurement data of contrast ratio versus laser power of single layer Te and Te alloys on polymethylmethacrylate substrates are reported. It is shown that these films can exhibit two regimes of hole formation depending upon laser power. In the lower power regime hole opening must be initiated by voids in the film while for higher powers voids are not necessary for hole opening. This interpretation leads to a better understanding of the hole ablation process as well as some practical consequences.
Effect of nonuniform piezoelectric films on monolithic surface acoustic wave devices
Authors: Bowers J. E. , Thornton R. L. , Khuri-Yakub B. T. , Jungerman R. L. , Kino G. S.
Published: February 2003

The effect of film thickness variation on the performance of ZnO on silicon surface acoustic wave delay lines is examined. The thickness variation obtained from a planar magnetron sputtering system with a 5-cm diameter erosion ring was measured and found to be in good agreement with the calculated thickness variation. This information, together with theoretical data on the dependence of surface acoustic wave velocity on ZnO film thickness, is used to predict phase distortions of 400° across 1-mm-wide, 2.5-cm-long delay lines. This high level of phase distortion was confirmed by experimental measurements with a laser probe.
Properties of high quality GaP single crystals grown by computer controlled liquid encapsulated Czochralski technique
Authors: Kokubun Y. , Washizuka S. , Ushizawa J. , Watanabe M. , Fukuda T.
Published: February 2003

The properties of GaP single crystals grown by an automatically diameter controlled liquid encapsulated Czochralski technique using a computer have been studied. A dislocation density less than 5×104 cm−2 has been observed for crystal grown in a temperature gradient lower than 70 °C/cm near the solid-liquid interface. Crystals have about 10% higher electron mobility than that of commercially available coracle controlled crystals and have 0.2∼0.5 compensation ratios. Yellow light emitting diodes using computer controlled (100) substrates have shown extremely high external quantum efficiency of 0.3%.
Solid-phase reactions of a polycrystalline silicon film with an overlapping aluminum film
Authors: Fukuda Yukio , Kohda Shigeto
Published: February 2003

Reactions betwen aluminum and polycrystalline silicon films below the eutectic temperature have been studied for a structure in which the aluminum film overlaps the polycrystalline silicon film on the SiO2 layer. The polycrystalline silicon in the overlapping location was found to be intensively dissolved into the aluminum film in comparison with the polycrystalline silicon with the aluminum film overlay. The aluminum substitution reaction for the polycrystalline silicon film was also found. The activation energy of the substitution reaction was about 1.0 eV, estimated from the dependence of the substituted aluminum length on the annealing temperature.
Deposition and reactive ion etching of molybdenum
Authors: Bensaoula Abdelhak , Wolfe J. C. , Oro James A. , Ignatiev A.
Published: February 2003

The stress in molybdenum films deposited by dc magnetron sputtering in neon has been characterized. Fabrication of 1-μ-thick films 2 cm in diameter on polyimide membranes has been achieved with low-stress material. A reactive ion etching process is described with 75-nm resolution and 15:1 aspect ratios.
Fermi levels in solution
Authors: Bockris John O’M. , Khan Shahed U. M.
Published: February 2003

The conventional concept that there is a so-called Fermi level for electronic states in solution which can be identified with the reversible potential on the vacuum scale of a redox couple present in solution (and in equilibrium with an electrode therein) is not valid. The inner potential of the solution phase should be added to the redox potential (on the vacuum scale) to achieve identity (at equilibrium) with the Fermi level energy of the electron in the metal to that in the solution.
Structure-dependent threshold current density in InGaAsP quantum well lasers
Authors: Sugimura Akira
Published: February 2003

Threshold current density is studied theoretically for InGaAsP multiple quantum well lasers by including the Auger recombination process. All the possible transitions between quantized subbands of two-dimensional carriers are taken into account in evaluating radiative and Auger processes. The Auger recombination current depends strongly on the quantum well structure, resulting in the necessity for an elaborate structure design. A design procedure is elucidated for the structure which gives the lowest threshold current density for InGaAsP multiple quantum well lasers.
Cerium-activated Gd2SiO5 single crystal scintillator
Authors: Takagi Kazumasa , Fukazawa Tokuumi
Published: February 2003

Cerium-activated phosphors are characterized by their fast luminescence decay. Gadolinium orthosilicate (Gd2SiO5) is a material possessing a high atomic number, and can also play host to the cerium activator. Cerium-doped Gd2SiO5 single crystals were grown by the Czochralski technique, and their luminescence properties were examined. The light output was 1.3 times larger than that of the best Bi4Ge3O12, and the decay constant was 60 ns at room temperature.
Shallow zinc diffusion in liquid phase epitaxial GaAs and (GaAl)As at 600 °C
Authors: Blum S. E. , Small M. B. , Gupta D.
Published: February 2003

The diffusion of zinc into GaAs and (GaAl)As was studied using a high resolution microsectioning technique. Diffusions were performed into epitaxially grown thin layers comparable to those used in injection laser structures; several boat grown GaAs were also studied. The diffusions were done at a temperature commonly used in device processing; a three-phase diffusant was used to preclude sample dissociation and damage. A diffusion coefficient of Zn in GaAs of 1.4×10−11 cm2 s−1 was obtained, and this is in good agreement with the extrapolation of the values obtained at higher temperatures. A marked difference in the diffusion profiles of GaAs and (GaAl)As was observed.
Diffusion length of moles in n-InP
Authors: Diadiuk V. , Groves S. H. , Armiento C. A. , Hurwitz C. E.
Published: February 2003

By measuring the photocurrent as a function of reverse bias for InP photodiodes with a range of junction depths, the hole diffusion length Lp of epitaxial n-type InP (n∼1.5×1016 cm−3) was determined to be approximately 12 μm. This value of Lp is an order of magnitude larger than that determined by the electron beam induced current and surface photovoltage techniques. Reasons for these discrepancies, which involve geometrical and material considerations, respectively, are discussed.
Reversible photoinduced modification of electron-capture cross section at localized states in a-Si:H
Authors: Okushi H. , Miyagawa M. , Tokumaru Y. , Yamasaki S. , Oheda H. , Tanaka K.
Published: February 2003

A reversible photoinduced modification of the electron-capture cross section at localized states in P-doped a-Si:H has been directly observed, being associated with the Staebler–Wronski effect. Isothermal capacitance transient spectroscopy measurement shows that the electron-capture cross section at the gap states located at around 0.5 eV below the conduction-band mobility edge (Ec) increases after the band-gap illumination and is nearly restored to its original value by thermal annealing below 200 °C. It has been suggested that a metastable state related with the dangling bond is created through the multiphonon emission when excess carriers recombine.
A high-power, single-mode laser with twin-ridge-substrate structure
Authors: Wada M. , Hamada K. , Shimizu H. , Sugino T. , Tajiri F. , Itoh K. , Kano G. , Teramoto I.
Published: February 2003

The structure of stripe-geometry lasers is reported, in which a double heterostructure with a very thin active layer is fabricated on a substrate with two parallel ridges. It is shown that the structure is very much fitted for the high-power, single-mode oscillation. The maximum cw output obtained is approximately 100 mW/facet, which is the highest power output ever attained in fundamental transverse mode devices. The far-field beam divergences parallel and perpendicular to the junction plane are as small as 6° and 16°, respectively.
Complete experimental evaluation of the carrier dependence of the refractive index from the frequency modulation spectra of single mode injection lasers
Authors: Sommers H. S.
Published: February 2003

A new method of evaluating the dependence on carrier density of the propagation constant of the excited mode of a semiconductor laser biased above threshold is applied to a single mode confined double heterostructure-large optical cavity laser operated at 8-mW dc. The method combines the measurements of the Fabry–Perot spectrum of the modulated laser, the relative modulation amplitudes of the coherent and short-wavelength spontaneous powers and the phase difference between the two, and the dependence on dc current of the two emissions. The evaluation is independent of the model of the lasing state, the reduction of the raw data requiring only subthreshold relations between current, voltage, carrier density, and spectrum. The change of the index of refraction of the waveguide mode with the concentration of electron-hole pairs in the recombination region is +1.8×10−22 cm3. Striking inconsistencies among various published accounts indicate a need for critical examination of all such studies.
cw room-temperature operation of GaAlAs single quantum well visible (7300 Å) diode lasers at 100 mW
Authors: Burnham R. D. , Lindström C. , Paoli T. L. , Scifres D. R. , Streifer W. , Holonyak N.
Published: February 2003

100-mW room-temperature cw laser operation at 7300 Å has been achieved in a Ga1−xAlxAs (x∼0.22), ∼300 Å thick, single quantum well double heterostructure diode grown by organometallic vapor phase epitaxy. The proton-delineated stripe contact is 6 μm wide, and the front and rear laser facets are coated for antireflection and high reflection respectively. The cw threshold current is 86 mA for a 250-μm-long device, and linear output power versus current characteristics are observed up to 100 mW with an external differential quantum efficiency of 1 W/A (59%). cw output power exceeds 13 mW at 100 °C. Between 25–55 °C, the pulsed threshold current varies exponentially with temperature T as exp(T/T0), where T0∼187 K.
Infrared optical constants of PtSi
Authors: Pimbley J. M. , Katz W.
Published: February 2003

Knowledge of the infrared optical constants of PtSi is required for quantum yield calculations of Schottky barrier IR imagers with PtSi electrodes. We employ Rutherford backscattering spectrometry to identify the PtSi phase and calculate the infrared optical constants from reflectance data by a Kramers–Kronig analysis technique. Several examples of quantum yield calculations for different imager structures using the calculated optical constants are given.
Bifurcation of deep levels in metastable (GaAs)1−xGe2x alloys
Authors: Newman Kathie E. , Dow John D.
Published: February 2003

Deep impurity levels in metastable (GaAs)1−xGe2x alloys are predicted to bifurcate as functions of x at the alloy order-disorder transition composition.
Integrated surface acoustic wave/field-effect transistor high-speed analog memory
Authors: Green J. B. , Kino G. S. , Walker J. T. , Shott J. D.
Published: February 2003

A totally monolithic buffer memory has been demonstrated whose operation is governed by the interaction between surface acoustic waves and an integrated multiplexed field-effect transistor array. The device is based on ZnO on Si surface acoustic wave technology with the field-effect transistor array being fabricated using a standard negative metal-oxide-semiconductor processing schedule. Experimental results are presented which show the low-speed readout of rf modulated waveforms (f0≊100 MHz), previously stored in the device.
Thermophonic investigation of switching and memory phenomena in thick amorphous chalcogenide films
Authors: Kotz J. , Shaw M. P.
Published: February 2003

We report the results of thermophonic experiments and numerical analyses of bias-induced threshold switching and memory effects in amorphous films of Ge15Te81S2Sb2. Our results corroborate the view that the initiation and maintenance of a threshold switching event are fundamentally electronic processes.
Undoped, semi-insulating GaAs layers grown by molecular beam epitaxy
Authors: Temkin H. , Hwang J. C. M.
Published: February 2003

Growth of undoped layers of GaAs by molecular beam epitaxy is reported. The resistivity of these layers is consistently greater than 106 Ω cm. Low-temperature photoluminescence measurements show well resolved exciton bands characteristic of very pure GaAs. The main contaminant is identified as carbon, at an extremely low level, and the spectra are completely free of any carbon-induced defect bands. The results suggest that the high resistivity of these layers is due to reduction of the background carbon level and the resulting close compensation of residual donors.
Surface potential relaxation in a biased Hg1−xCdxTe metal-insulator-semiconductor capacitor
Authors: Daugherty M. , Janousek B. K.
Published: February 2003

Biased metal-insulator-semiconductor (MIS) capacitors are known to exhibit a flatband voltage shift which is logarithmic in time. This phenomenon has been attributed to charge exchange between the semiconductor surface and a set of insulator traps distributed either in energy or in depth. It is shown that logarithmic time dependence is also an attribute of a simple capture model which incorporates the relaxation of the semiconductor surface potential which occurs as the density of total trapped charge changes. The predictions of this model are compared with experimental results obtained from a biased MIS structure comprising 600 Å of native oxide on n-type Hg0.70Cd0.30Te.
Third-order optical nonlinearity induced by effective mass gradient in heterostructures
Authors: Yuen S. Y.
Published: February 2003

In semiconductor heterostructures the electron effective mass can vary spatially, giving rise to a nonlinear force parallel to the mass gradient. In an optical field this nonlinear force modulates the electron mass through its position dependence, leading to a novel third order optical nonlinearity. The susceptibility of this process is calculated through the kinetic equations for the electrons. It is found that large nonlinear refractive indices can be obtained with subpicosecond relaxation times. Possible device configurations are discussed.
Optically integrated coherently coupled AlxGa1−xAs lasers
Authors: Levine B. F. , Logan R. A. , Tsang W. T. , Bethea C. G. , Merritt F. R.
Published: February 2003

We have succeeded for the first time in integrating on the same chip, two electrically independent lasers which are coherently coupled via the overlap of their lateral optical fields. Such coupled lasers show excellent single longitudinal mode characteristics which are considerably improved over that of the individual lasers. They are therefore promising devices for high data rate optical communication systems.
Electrical and optical properties of InP grown by molecular beam epitaxy using cracked phosphine
Authors: Chow Robert , Chai Young G.
Published: February 2003

InP was grown by molecular beam epitaxy on InP(100) substrates using In and phosphorus cracked from PH3. The dependence of the electrical and optical properties of the films on the substrate and cracking furnace temperature is discussed. One film had 40% the photoluminescence intensity of that from an InP bulk standard, an unintentional background-doping concentration of 1×1016 cm−3, and a mobility of 12 250 cm2/V at 77 °K. The lowest unintentional background doping concentration obtained was 2.1×1015 cm−3 at 77 °K. Surface morphology was excellent for a substrate temperature of 400 °C.
Electroluminescence in hydrogenated amorphous silicon-carbon alloy
Authors: Munekata Hiro , Kukimoto Hiroshi
Published: February 2003

White electroluminescence (EL) was observed for the first time in the hydrogenated amorphous silicon-carbon alloy a-SixC1−x:H(x=0.2–0.4) at room temperature. Experiments were carried out for the devices which consisted of an amorphous film sandwiched between two insulating layers of Y2O3. EL is observable above a threshold ac voltage of 100 V. The EL spectrum is slightly different from the photoluminescence spectrum of the amorphous film.
Novel fine line patterning technique for submicron devices based on selective oxidation of aluminum
Authors: Nulman Jaime , Krusius J. Peter
Published: February 2003

A novel fine line patterning technique for the fabrication of submicron devices is described. It is based on local oxidation and anisotropic dry etching of an aluminum film acting as a substitutional mask. Etch selectivities greater than 4:1 between plasma oxidized and unoxidized aluminum have been observed. 1500-Å-wide lines with essentially vertical walls have been achieved with this technique. These Al patterns can either be used directly in device structures or as masks for the etching of underlying layers.
Channeling studies of Ge-GaAs superlattices grown by molecular beam epitaxy
Authors: Chang Chin-An , Chu Wei-Kan
Published: February 2003

(100) Ge-GaAs superlattices grown by molecular beam epitaxy have been analyzed using He+ ion channeling spectrometry. Over the individual layer thickness of 25–100 Å for Ge and GaAs in the superlattices, very low dechanneling yields are observed along the 〈110〉 axis. Dechanneling yields along the [100] growth direction, however, are low only for the thicker layer structure, and become increasingly larger than the 〈110〉 ones for the thinner layer structures. These results are opposite to the ones for the InAs-GaSb superlattices where dechanneling yields along the 〈110〉 axis are much higher than the [100] ones for all the superlattices studied. The channeling results are compared with those using other techniques and their implications on the Ge-GaAs interfaces discussed.
Electron spin resonance of dangling bonds in highly disordered layers produced by ion implantation in GaP
Authors: Matsumori T. , Miyazaki K. , Shigetomi S.
Published: February 2003

Electron spin resonance spectrum, which can be interpreted to be due to dangling bonds in highly disordered layers produced by 200-keV N-ion implantation in GaP crystals, has been observed. The spectrum is symmetrical, Lorentzian, and isotropic with g=2.0032+0.0004 and a linewidth of ∼6 G and appears only in the case of high dose implantation at doses of 5×1015 cm−2 or above. The isochronal annealing curve of the spectrum has two normal annealing stages and one reverse annealing stage. The reverse and the subsequent normal annealing stages shift toward higher temperatures with increasing ion dose.
A low-scattering graded-index SiO2 planar optical waveguide thermally grown on silicon
Authors: Zelmon David E. , Jackson Howard E. , Boyd J. T. , Naumaan A. , Anderson D. B.
Published: February 2003

Planar graded-index SiO2 optical waveguides characterized by very low scattering have been fabricated on silicon substrates by thermal oxidation. Three samples having thicknesses on the order of 15 μm are characterized by waveguide losses less than 1 dB/cm. The appearance of the waveguide streak and out-of-plane scattering measurements using photon counting indicate extremely low scattering. The low scattering along with the weak field confinement present in the graded-index waveguides is consistent with the dominant waveguide loss being due to coupling to the silicon substrate.
Proton and deuteron bombarded Ga0.47In0.53As
Authors: Steeples K. , Dearnaley G. , Harwell A. E. R. E. , Saunders I. J.
Published: February 2003

Large increases in resitivity of Ga0.47In0.53 As have been observed due to bombardment with hydrogen ion isotopes. After damage factors due to mass and dose of the implanted isotopes have been taken into account, the high resistivity values of proton and deutron bombarded Ga0.47In0.53 As agree,k contrasting with previous observations in GaAs. An explanation is offered.
Signal-to-noise ratio for magneto-optic readout from quadrilayer structures
Authors: Connell G. A. N. , Treves D. , Allen R. , Mansuripur M.
Published: February 2003

We present an experimental investigation of our earlier theoretical predictions regarding the signal-to-noise ratio for magneto-optic readout from quadrilayer structures in a differential detection scheme. Using quadrilayer structures employing amorphous Tb-Fe alloys as the magnetic material, quartz as the dielectric material, and aluminum as the reflecting material, we show that the signal enhancement predicted for quadrilayers occurs even when the numerical aperture of the readout system is large, a crucial result for their effectiveness in magneto-optic storage applications. We also show that the signal-to-noise ratios measured are in quantitative agreement with theory.
Ag photodoping of amorphous chalcogenides
Authors: Lis S. A. , Lavine J. M.
Published: February 2003

Spectral measurements over the wavelength range of 400–800 nm on As2S3, As2Se3, and GeSe2, measurements on a tuned structure of As2S3, and exact calculations on a multifilm structure support the recent suggestion that the photons relevant to the photodissolution of Ag are absorbed in the Ag and not in the chalcogenide. The observed spectral dependence may be fitted by an internal photoemission model.
Recombination enhanced dislocation glide in InP single crystals
Authors: Maeda K. , Takeuchi S.
Published: February 2003

The glide mobility of dislocations in bulk n-type InP single crystals was measured by the double-etching method as a function of temperatures with or without 30-keV electron beam irradiation. The mobility of β dislocations was found to be enhanced by the irradiation in such a manner that the mobility increase is caused by a decrease in the apparent activation energy, which is characteristic of recombination enhanced defect reaction phenomena. The enhancement is not much different in its magnitude from the same type of dislocations in GaAs.
Broadband guided-wave optical frequency translator using an electro-optical Bragg array
Authors: Kingston R. H. , Becker R. A. , Leonberger F. J.
Published: February 2003

We describe a new type of optical frequency translator which utilizes Bragg diffraction from a traveling index wave produced by an interdigitated electrode grating on a LiNbO3 surface waveguide. The grating is driven by a three-phase electrical signal that results in a unidirectional wave with a fixed Bragg angle determined by the electrode spacing. The diffraction thus produces a single-sideband suppressed carrier optical output. Measurements at 10 and 100 MHz have yielded greater than 90% carrier-to-sideband conversion efficiency with over 100:1 suppression of the carrier and unwanted sideband. The device should be operable from arbitrarily low frequencies up to several gigahertz.
Measurement of high electron drift velocity in a submicron, heavily doped graded gap AlxGa1−xAs layer
Authors: Levine B. F. , Bethea C. G. , Tsang W. T. , Capasso F. , Thornber K. K. , Fulton R. C. , Kleinman D. A.
Published: February 2003

We have directly determined a high velocity (v=2×107 cm/s) for electrons in a submicron (0.42 μm), strongly graded (quasifield F=8.8 kV/cm) highly doped ( p=4×1018 cm−3) AlxGa1−xAs layer. A transit time of only 1.7 ps was measured (an order of magnitude shorter than that for F=1.2 kV/cm). Such a structure would be ideal for the low resistance base of a high-speed n-p-n transistor.
Formation of MoSi2 by pulsed electron beam irradiation onto a vapor deposited molybdenum/silicon structure
Authors: Suzuki Setsu , Ohkubo Yasushi , Matsuoka Fumitomo , Itoh Tadatsugu
Published: February 2003

A molybdenum disilicide layer was formed by pulsed electron beam irradiation onto a vapor deposited Mo film on a Si substrate. The electron beam with a duration of almost 1 μs was generated by glow discharge of He at a pressure of 1×10−5 Torr in a vacuum chamber equipped with a capacitor of 1 μF that was charged at 7 kV. The total energy stored in the capacitor was 25 J and the irradiated area was almost 1 in. in diameter. The qualitative and structural characterizations were performed by Auger electron spectroscopy (AES), transmission electron diffraction (TED), and transmission electron microscopy (TEM). A depth profile by AES showed that a uniform MoSi2 layer was formed toward the Mo surface from the Mo/Si interface and that C and O contaminants were swept away from the silicide. The hexagonal MoSi2 phase was uniquely identified in the irradiated layer and the TEM micrographs showed uniform polycrystalline grains of a size of 800 Å.
Effect of anodic growth temperature on native oxides of n-(Hg, Cd)Te
Authors: Bertagnolli E. , Bettini M. , Gornik E.
Published: February 2003

The insulating behavior of anodically grown native oxides on Cd0.23Hg0.77Te can be improved considerably by performing the anodic process at increased temperatures. For the first time, anodic oxides were grown at 50 °C in the standard ethylene glycol-KOH-electrolyte which show a reduction in the high-frequency (1 MHz) conductivity of the order of one magnitude respective to our room-temperature grown oxides. A high electrical breakdown voltage (1.5 MV/cm) and a decreased hysteresis shift (50 mV) underline these results. Other oxide parameters such as fixed oxide charges and fast surface states and the excellent dc resistivity remain practically unchanged. Subroom-temperature grown oxides, however, are extremely unstable.
Shallow donor associated with the main electron trap (EL2) in melt-grown GaAs
Authors: Walukiewicz W. , Lagowski J. , Gatos H. C.
Published: February 2003

A systematic analysis of Hall effect measurements on a large number of melt-grown GaAs crystals with different concentrations of the major deep trap (EL2) revealed the presence of a new shallow donor level (20–30 meV below the conduction band) with concentrations similar to those of the EL2. This finding indicates that the EL2 center is a double donor consisting of the deep EL2 donor at Ec−0.76 eV and a shallow donor state. The presence of the shallow donor state should have important consequences in the formulation of a compensation mechanism in semi-insulating GaAs.
Optical pulse compression by nonlinear coupling
Authors: Kitayama Ken-ichi , Wang Shyh
Published: February 2003

Nonlinear coupled waveguide is studied for optical pulse compression, utilizing the power-dependent performance of such waveguides caused by the intensity-dependent refractive index in the region of interaction. Theoretical calculations predict that the pulse compression to less than 1/5 of the original pulse width is achievable with a loss of 3 dB.
Continuously operated visible-light-emitting lasers using liquid-phase-epitaxial InGaPAs grown on GaAs substrates
Authors: Mukai S. , Yajima H. , Mitsuhashi Y. , Shimada J. , Kutsuwada N.
Published: February 2003

Continuously operated visible-light-emitting InGaPAs lasers are fabricated using liquid-phase-epitaxial wafers grown on a GaAs substrate. The wavelength is 785 nm. The lowest threshold current is 80 mA (6 kA/cm2 in current density). The highest quantum efficiency is 33%. The characteristic temperature is 135 K. The InGaPAs lasers free from dark line defects are presumably grown on GaAs.
Amplification of sound by conduction electrons in a piezoelectric superlattice
Authors: Ketterson J. B. , Wong G. K.
Published: February 2003

It is shown that the amplification coefficient of sound with a wave vector corresponding to a Brillouin zone edge of a superlattice structure containing at least one piezoelectric component is resonantly enhanced with respect to other wave vectors in the presence of an electron drift velocity which exceeds the sound velocity.
Impact ionization near GaAs grain boundaries
Authors: Pike G. E. , Gourley P. L. , Kurtz S. R.
Published: February 2003

Electroluminescence from a GaAs bicrystal has been measured at high current densities, and gives direct evidence of impact ionization near the grain boundary. Negative differential capacitance is seen at lower current densities and is associated with barrier height modulation by minority carriers.
Diode lasers of lead-europium-selenide-telluride grown by molecular beam epitaxy
Authors: Partin D. L.
Published: February 2003

It is desirable to extend the wavelength coverage of PbSnTe diode lasers to shorter wavelengths (λ<5 μm) and higher operating temperatures. Currently, this range is covered by PbSxSe1−x diode lasers operating below 100 K. Double heterojunction diode lasers have now been fabricated using a new materials system, Pb1−xEuxSeyTe1−y. These structures were grown lattice matched to (100) oriented PbTe substrates by molecular beam epitaxy using PbTe, Eu, Te, PbSe, Tl2Te (p dopant), and Bi2Te3 (n dopant) source ovens. Mesa diodes were fabricated with 20-μm-wide stripes using anodic oxide insulation. Diodes have so far been fabricated with up to x=0.010, y=0.011, which operated cw from 4.93 μm (at 30 K) to 4.06 μm (at 136 K). Diodes with x=0.0015, y=0.0020 have operated up to 147 K cw. This is the highest cw operating temperature ever attained with lead-chalcogenide diode lasers. A wide range of single mode operation with ∼1 mW output power was observed for some of the better diodes. These diodes are useful for ultrahigh resolution spectroscopy, and may be useful in the future for low-loss, long-wavelength fiber optics communications.
17-GHz bandwidth electro-optic modulator
Authors: Gee C. M. , Thurmond G. D. , Yen H. W.
Published: February 2003

A high-speed integrated-optic Ti:LiNbO3 Mach–Zehnder interferometric modulator for 0.83-μm wavelength operation has been fabricated and characterized. The modulator exhibits smooth, resonance-free frequency response with a 17-GHz 3-dB bandwidth. The modulator has a built-in phase bias of π/2 for maximum linearity. Complete intensity modulation can be achieved with 120-mW drive power. Optical modulation was measured up to 18 GHz directly by using a very high-speed photodiode and indirectly using the swept frequency technique.
Single-longitudinal mode performance characteristics of cleaved-coupled-cavity lasers
Authors: Tsang W. T. , Olsson N. A. , Logan R. A. , Ditzenberger J. A. , Kaminow I. P. , Ko J.-S.
Published: February 2003

The single-longitudinal mode performance characteristics of cleaved-coupled-cavity (C3) lasers were studied. A high-speed direct modulation technique for increasing the dynamic range of modulation and for obtaining complete depth of modulation of the optical output power while maintaining single-frequency operation was proposed and demonstrated.