bluuebunny/crossref_metadata_2025 huggingface dataset:
Additive coloration of sapphire
Authors: Lee K. H. , Crawford J. H.
Published: February 2003

F-type centers have been introduced in to single crystals of α-Al2O3 by heating them at 2000 °C in a graphite crucible under strongly reducing conditions. This treatment produces results similar to additive coloration in that anion vacancies charge compensated by electrons are introduced as demonstrated by the presence of a 6.1-eV optical absorption band after heating. Although the same band can be created by high-energy-particle bombardment; by contrast those resulting from this additive coloration procedure are very stable against thermal annealing. Annealing above 1400 °C in air is necessary to produce a decrease in the 6.1-eV-band amplitude. The 6.1-eV band has been related to the F center in our previous study. This study further substantiates this model.
p-n junction formation in boron-deposited silicon by laser-induced diffusion
Authors: Narayan J. , Young R. T. , Wood R. F. , Christie W. H.
Published: February 2003

A technique for p-n junction formation in silicon, based on deposition of boron on silicon at room temperature followed by laser irradiation is described. Transmission electron microscopy and electrical measurements indicate that as a result of the laser irradiation the boron is dissolved in the silicon and becomes electrically active. Diode characteristics of p-n junctions produced by this technique are quite good. The dopant profile distribution has been obtained using secondary ion mass spectrometry and is in qualitative agreement with simplified theoretical calculations.
Auger-electron-spectroscopy (AES) measurements on anodically oxidized layers of single-crystal GaP
Authors: Okada Akira , Ohnuki Yasuhide , Inada Taroh
Published: February 2003

Anodically oxidized layers were grown on GaP (111) surfaces from a solution of N-methyl acetamide, H2O, NH4OH, and citric acid having a pH value of 9.0. The layer growth rate was 11 Å/V with a constant current density of 0.5 mA/cm2. Auger electron spectra and depth profiles of the components were measured. The phosphorous L3M2,3M2,3 transition at 117 eV suffered a chemical shift in the oxide layers, and the shape of the first derivative of the Auger signal was completely different from that observed with P in GaP. Observation of the phosphorous K L2,3L2,3 transition at 1858 eV indicated that the ratio of P/Ga had a constant value throughout the oxide layers. Only the oxygen concentrations varied along with the depth.
Effect of surface condition on diffusion in thin films at low temperatures
Authors: Hwang J. C. M. , Ho P. S. , Balluffi R. W.
Published: February 2003

The effect of surface condition on the out-diffusion of atoms through a thin film to the free surface has been analyzed by considering the coupling between grain boundary diffusion and surface diffusion. It is demonstrated that under certain circumstances, the surface diffusion rate can have a large effect on the measured rate of diffusion through the thin film. In the analysis for the cases involving out-diffusion, the surface is treated as a sink of finite capacity and the saturation level of material accumulation at the surface is discussed in terms of a surface-segregation ratio. This analysis can qualitatively explain some of the recent experimental observations on the effect of the annealing ambient on out-diffusion. The opposite but similar problem of the effect of the source surface condition on the rate of in-diffusion from the surface has also been discussed.
The incorporation of Ga during LPE growth of In0.53Ga0.47As on (111)B and (100) InP substrates
Authors: Antypas G. A. , Houng Y. M. , Hyder S. B. , Escher J. S. , Gregory P. E.
Published: February 2003

We report the temperature dependence of the incorporation of Ga during LPE growth of In0.53Ga0.47As on (111) B- and (100) -oriented InP substrates. The distribution coefficients of Ga can be accurately represented by KGa(111)B =6.40×10−6 exp(1.10/kT) and KGa(100)=5.02×10−13 exp(2.37/kT), which are equal at 629 °C. The difference in activation energies is the source of the ’’discrepancy’’ reported by Pearsall etal. that KGa(111)B<KGa(100) at 621 °C while from our results KGa(111)B≳KGa(100) at 650 °C.
Discrimination and state stability of S=1 and 0 bubbles in a field access racetrack
Authors: Konishi S. , Watanabe F. , Shibata N. , Narita K.
Published: February 2003

Discrimination of S=1 and 0 bubbles using dynamic bubble collapse and a state-stability test under quasistatic translation were tried for a YY-pattern racetrack on a 3-μm bubble film with a YIG capping layer. The bias-field margin for collapse discrimination was 5 Oe. These two states were stable for 140–160 Oe of bias field and for 25–50 Oe of rotating in-plane field.
Epitaxial regrowth of evaporated amorphous silicon by a pulsed laser beam
Authors: Révész Péter , Farkas Gyözö , Mezey Gábor , Gyulai József
Published: February 2003

3000-Å-thick epitaxial layers of 〈100〉 and 〈111〉 silicon have been grown using a Q-switched ruby laser. The initial amorphous silicon layers were formed by e-gun evaporation of high-purity silicon. Using Rutherford backscattering it was established that the crystal quality of the regrown 〈100〉 Si is much better than the 〈111〉 Si, similar to thermal annealing.
Annealing behavior of nitrogen-implanted proton-irradiated molybdenum
Authors: Anttila A. , Hirvonen J.
Published: February 2003

The irradiation effect of 0.45-MeV protons on the solubility and diffusivity of interstitial impurities has been studied by annealing nitrogen-implanted molybdenum samples in the temperature region 600–800 °C. The nondestructive (p,γ) resonance-broadening method was applied as a probe for the nitrogen. Even for the low proton irradiation doses, a remarkable increase in solubility and a decrease in diffusivity were observed.
An ion-beam study of Sb trapping in Fe-Ti-Sb-C alloys
Authors: Myers S. M. , Follstaedt D. M. , Rack H. J.
Published: February 2003

Using ion-backscattering analysis and transmission electron microscopy of ion-implanted alloys, it is shown that TiC precipitates in Fe are effective traps for Sb. This trapping is proposed as a contributing mechanism for the reduced temper embrittlement susceptibility observed in steels containing Ti.
Large-signal gain and intensity enhancement in a backward Raman amplifier
Authors: Murray J. R. , Goldhar J. , Eimerl D. , Szöke A.
Published: February 2003

Saturation effects have been investigated in a KrF laser-pumped backward Raman amplifier using methane gas. Pump depletion of 30% with an intensity gain of 2 has been demonstrated, and the results are shown to be consistent with a simple Frantz-Nodvik saturation treatment.
The observation of melt carryover in the active layer of LPE GaAs/GaAlAs double-heterostructure laser material
Authors: Wakefield B.
Published: February 2003

The use of a photoluminescence technique to reveal the presence of carryover in the active layer of LPE GaAs/GaAlAs double-heterostructure laser material has enabled growth procedures to be optimized in order to produce uniform active layers.
Measurement of excited-state-absorption loss for Ce3+ in Y3Al5O12 and implications for tunable 5d→4f rare-earth lasers
Authors: Jacobs Ralph R. , Krupke William F. , Weber Marvin J.
Published: February 2003

Broad bandwidth 5d→4f transitions in Ce3+ have been considered for tunable laser action. In this letter, optical probe measurements of excited Ce3+ ions in Y3Al5O12 show that stimulated emission in the 550–610-nm region is not possible at 295 K because of excited-state absorption. Transient measurements demonstrate that part of this loss has ≈75-ns lifetime and is associated with absorption from the lowest 5d level; a longer-lifetime loss is also observed. The excited-state-absorption loss is reduced at lower temperatures.
Acoustic harmonic generation at unbonded interfaces and fatigue cracks
Authors: Buck O. , Morris W. L. , Richardson J. M.
Published: February 2003

The generation of a second-harmonic signal at a flat unbonded interface between two solids has been observed. This signal is caused by passage of a longitudinal acoustic wave across the interface. The harmonic amplitude depends upon the pressure applied normal to the interface and is largest close to zero pressure, as expected theoretically. The effect has also been used to detect the presence of microcracks on the surface of Al 2024, developed during fatigue.
Double-focusing diode
Authors: Takagi Ken’ichi
Published: February 2003

Applying a coaxial Marx generator with the rectangular pulse across a constant load for a study of double-focusing diodes, an important difference of the behavior between the single- and the double-focusing diode is found. In order to understand its behavior more precisely, the necessity will be pointed out to take into account the anode plasma effects.
Formation of a copper-oxygen-polymer complex on polystyrene
Authors: Burkstrand James M.
Published: February 2003

Previous studies have indicated an increase in the adhesion of deposited metal films to commercial polymers when additional carbon-oxygen bonds were present on the polymer surface. In this work, we report the changes taking place on an oxygen-treated polystyrene surface following vapor deposition of copper. We first found that atomic oxygen produces a carbon-oxygen single bond on the polystyrene surface, with the oxygen displacing a hydrogen and either forming an OH group or cross linking two chains. In addition, this bond is strongly perturbed after vapor deposition of copper. The deposition of copper results in the formation of a copper-oxygen-polymer complex on the surface, the exact nature of which is still to be determined. The formation of such a complex is consistent with an increased adhesive strength of copper on oxygen-treated polystyrene.
Open-circuit voltage of vertical-junction photovoltaic devices at high intensity
Authors: Ekstedt Thomas W. , Mahan John E. , Frank Robert I. , Kaplow Roy
Published: February 2003

Vertical single-junction silicon photovoltaic cells show a steady increase in open-circuit voltage with increasing incident light intensity of approximately 0.1 V per decade of intensity, up to approximately 100 W/cm2 (∼1000 suns). Voltages as high as 0.76 V have been observed at 25 °C with no apparent saturation of voltage at high intensity. Measurements are presented for cells of various base doping levels. An efficiency of 19.1% has been observed at 76 W/cm2 and 25 °C using an unfiltered xenon short-arc lamp for a nonoptimized cell.
A revised model for the oxidation of Si by oxygen
Authors: Blanc Joseph
Published: February 2003

A conceptually simple modification of the Deal-Grove model for oxidation of Si by dry oxygen provides an excellent fit to experimental data while removing the regime of ’’anomalously high’’ initial oxidation rates inferred by previous workers. The essential physical proposal is that while diffusion through the amorphous oxide is via molecular oxygen, Si oxidation occurs through the reaction of a small concentration of atomic oxygen.
Radiation damage in ion-implanted GaP and GaAs0.6P0.4
Authors: Rothemund W. , Fritzsche C. R.
Published: February 2003

Electron-beam-absorption measurements were performed to investigate the formation and annealing of radiation damage produced by ion implantation into GaP and GaAs0.6P0.4. The fluence FA required to yield an amorphous layer, the dependence of FA on ion mass and target temperature, and the temperatures necessary for annealing were determined. For 140-keV Ar into GaAs0.6P0.4, we found FA=1×1014 cm−2 at 273 K and FA→∞ at 580 K. Our results compare well with known data for GaAs and GaP and demonstrate the applicability of the new method of measurement.
XeF* and KrF* waveguide lasers excited by a capacitively coupled discharge
Authors: Newman L. A.
Published: February 2003

The operation of XeF* and KrF* waveguide lasers excited by a capacitively coupled self-sustained discharge is described. Output energies of 35 and 50 μJ, peak powers of 3.5 and 15 kW, and FWHM pulse widths of 10 and 3 nsec have been obtained for XeF* and KrF*, respectively, with an intrinsic efficiency of 1%. Double-pulse experiments were conducted to evaluate the repetition rate potential of this device.
Simple two-step photoionization yields high densities of laser-active F2+ centers
Authors: Mollenauer L. F. , Bloom D. M. , Guggenheim H.
Published: February 2003

A selective two-step process is described for the photoionization of F2 centers. An electron trap density no greater than that of the original F2 center population is required for ∼100% ionization, and only modest light intensities are required (I∼10 W/cm2 or less). Certain divalent transition-metal ions have been found to make excellent traps. The two-step process has allowed the production of F+2 center densities ∼1018/cm3, as needed for the construction of efficient lasers.
Enhanced photoelectrochemical solar-energy conversion by gallium arsenide surface modification
Authors: Parkinson B. A. , Heller A. , Miller B.
Published: February 2003

In the n-GaAs/Se=–Se=x–OH−/C liquid junction solar cell, modification of the semiconductor surface by incorporation of ruthenium increases both the fill factor and the open-circuit voltage and improves the reproducibility of performance. The power conversion efficiency of the modified cell is 12% under ∼100 mW/cm2 sunlight. Surface metal atoms or ions are shown to alter GaAs cell behavior widely; Ru represents a case for which the effect on cell performance is both positive and persisting.
Composition dependence of the influence of lattice mismatch on surface morphology in LPE growth of InGaAsP on (100) -InP
Authors: Feng M. , Tashima M. M. , Windhorn T. H. , Stillman G. E.
Published: February 2003

The dependence of the surface morphology and the interface misfit dislocation density on the amount of lattice mismatch varies considerably with the composition of the quaternary material in the 1.15–1.31-μm band-gap range. For the same amount of lattice mismatch the surface morphology becomes poorer for the longer-wavelength material, and this causes melt removal problems in the LPE growth unless the lattice mismatch is less than 0.09%. For the growth of 1.31-μm band-gap material of good crystallographic quality, it is essential that the lattice mismatch be less than 0.03%.
Electric polarization behavior of MgO : Li+ crystals upon quenching from above 1400 K
Authors: Eisenberg D. J. , Cain L. S. , Lee K. H. , Crawford J. H.
Published: February 2003

Crystals of Li+-doped MgO which have been quenched from temperatures in excess of 1400 K exhibit an extraordinarily large polarization in an electric field, and the temperature dependence of the relaxation time of this polarization, as measured by both dc (thermal depolarization) and ac (loss tangent versus frequency) methods, indicates a relaxation activation energy of 0.6–0.73 eV, which is consistent with the ionization energy of [Li]° centers. This polarization behavior is to be expected for small semiconductor inclusions (regions of high [Li]° center density embedded in a dielectric) and supports the ’’microgalaxy’’ model of Chen et al. to account for stable [Li]° centers in annealed and quenched MgO : Li+ crystals.
Fresnel lens in a thin-film waveguide
Authors: Ashley Paul R. , Chang William S. C.
Published: February 2003

The theoretical intensity profile of a phase shift and absorption Fresnel lens in a thin-film waveguide has been calculated. An experimental lens has been constructed with F=5 and a focal length=4 mm using CeO deposited on a BaO waveguide. A 3-dB spot size (full width half-maximum) of 3 μm was obtained compared to a diffraction-limited spot size of 2 μm from theory. Efficiency is approximately 25% and a variation of less than 3 dB in peak intensity is observed over incident angles of up to ±15° from normal.
Saturated absorption in NH3 demonstrated using a tuneable diode laser
Authors: Jennings D. E.
Published: February 2003

Saturation of molecular transitions using a tuneable diode laser has been demonstrated for the first time using a standing-wave-cavity configuration with the laser beam focused at the sample. Observed saturation effects in NH3 transitions near 888 cm−1 include sub-Doppler (Lamb-dip) resonances at the line center.
vuv-pumped HgCl laser
Authors: Eden J. Gary
Published: February 2003

Photolytic pumping of the HgCl35(B→X) laser has been demonstrated. Oscillation at 557.6 and 558.4 nm was obtained by irradiating HgCl2 vapor and helium with incoherent Xe*2 emission at 172 nm from an e-beam-excited xenon plasma. Also, by photodissociating HgCl2 with ArCl* (175 nm) fluorescence, the HgCl(B) state radiative lifetime was determined to be 22.2±1.5 ns.
Collisional quenching kinetics for the HgCl* (B1/2) state
Authors: Mandl A. , Parks J. H.
Published: February 2003

Measurements of the rates of collisional quenching of HgCl* (B2 Σ+1/2) by He, Ar, Xe, N2, Cl2, HCl, and CCl4 are reported in this paper. Steady-state measurements are made of HgCl* fluorescence produced by photolyzing HgCl2 using Xe2* radiation. A background pressure of [Xe]⩾100 Torr ensures that the HgCl* is vibrationally relaxed and all the quenching measurements are from v′=0. He, Ar, and N2 showed no quenching for pressures <1000 Torr. Xe, Cl2, HCl, and CCl4 resulted in two-body quenching rates of 2.4×10−13, 1.3×10−10, 8.6×10−11, and 1.2×10−10 cm3/sec, respectively. These rates are derived by using an estimated HgCl* (B2 Σ+1/2) lifetime of 29 nsec.
Photoluminescence topographic observation of defects in silicon crystals
Authors: Nakashima Hisao , Shiraki Yasuhiro
Published: February 2003

A simple rapid nondestructive method of evaluating defects in silicon crystals is developed. This method is basically an observation of photoluminescence (PL) pattern or PL topography. The correlation between the PL topograph and the defects are examined by preferential etching. Stacking faults and dislocations which are known to adversely affect many devices are found to be observed as dark spots in the PL topograph.
Edge effect in high-resolution scanning Auger-electron microscopy
Authors: Shimizu R. , Everhart T. E. , MacDonald N. C. , Hovland C. T.
Published: February 2003

An edge effect observed in high-resolution scanning Auger-electron microscopy is modeled by Monte Carlo methods based on the direct simulation of individual inelastic scattering processes. The Monte Carlo method permits the simulation of the spatial distribution of excited electrons generated by inelastic scattering. The results suggest that high-energy excited (’’secondary’’) electrons are a significant source of Auger electrons (L-MM transition) in aluminum and play an important role in causing the edge effect.
Stable operation of buried-heterostructure Ga1−xAlxAs lasers during accelerated aging
Authors: Kajimura T. , Saito K. , Shige N. , Ito R.
Published: February 2003

The optical properties of buried-heterostructure Ga1−xAlxAs lasers are carefully studied during accelerated aging at 70 °C. It is shown that neither kinks nor self-pulsation is observed in the majority of the lasers after long-term aging, in contrast to the observations in conventional stripe-geometry lasers. The observed stable operation of buried-heterostructure lasers may be attributed to the transverse-mode stability and small cavity size intrinsic to the lasers.
Chirp-grating lens for guided-wave optics
Authors: Yao S. K. , Thompson D. E.
Published: February 2003

A high-throughput diffraction-limited chirp-grating Bragg diffraction lens for guided-wave optical device applications has been demonstrated with planar photolithographic fabrication techniques. Diffraction-limited performance has been obtained with a 2-mm-aperture f/16 lens focusing the He-Ne laser beam to a 6.1-μm spot size. The grating diffraction efficiency to the focus is over 90%. This type of lens has predictable focusing properties which are insensitive to process variations, an important consideration for accurately aligned integrated optical systems.
Pulse splitting in a mode-locked Nd : YAG oscillator
Authors: Siebert Larry D. , Montry Gary R.
Published: February 2003

Temporal pulse splitting has been observed at an aperture 8 m from a passively mode-locked Nd : YAG laser oscillator. A theoretical model using the published value of the nonlinear refractive index n2 of YAG shows the splitting mechanism.
Empirical approximations for the Fermi energy in a semiconductor with parabolic bands
Authors: Nilsson N. G.
Published: February 2003

Approximate expressions are presented which are useful for computing the position of the Fermi level in a semiconductor when the carrier concentration is known. A simple approximation formula is applicable for η=EF/kT⩽5.7, while an extended approximation can be used up to η⩽20, the error in EF being less than 10−2kT in both cases.
Organometallic vapor deposition of epitaxial ZnSe films on GaAs substrates
Authors: Stutius W.
Published: February 2003

Smooth epitaxial single-crystalline layers of (100) ZnSe on (100) GaAs substrates are grown by a new low-pressure low-temperature organometallic chemical vapor deposition process. The strong band-edge photoluminescence peak and the absence of any substantial luminescence intensity at longer wavelengths indicate an absence of deep trapping centers which is typically not observed in other CVD growth.
Electron mobilities in modulation-doped semiconductor heterojunction superlattices
Authors: Dingle R. , Störmer H. L. , Gossard A. C. , Wiegmann W.
Published: February 2003

GaAs-AlxGa1−xAs superlattice structures in which electron mobilities exceed those of otherwise equivalent epitaxial GaAs as well as the Brooks-Herring predictions near room temperature and at very low temperatures are reported. This new behavior is achieved via a modulation-doping technique that spatially separates conduction electrons and their parent donor impurity atoms, thereby reducing the influence of ionized and neutral impurity scattering on the electron motion.
A comparison of surface analysis using ion scattering, ion-produced photons, and secondary ion emission
Authors: MacDonald R. J. , Heiland W. , Taglauer E.
Published: February 2003

ISS, SIMS (recoil target ions), and ion-produced photon emission (IPP) from surfaces subject to low-energy ion bombardment have been compared by simultaneous measurement of the effect of reactive gas adsorption on each signal. A direct correlation between the three signal strengths has been established. Cross sections for desorption of CO from Ni due to low-energy ion bombardment have been measured independently and simultaneously by two of the three methods.
Photopumped laser operation of MO-CVD AlxGa1−xAs near a GaAs quantum well (λ≳6200 Å, 77 °K)
Authors: Dupuis R. D. , Dapkus P. D. , Kolbas R. M. , Holonyak N. , Shichijo H.
Published: February 2003

Data are presented showing that AlxGa1−xAs (x∼0.42) grown by metalorganic chemical vapor deposition (MO-CVD) will operate as a photopumped laser to wavelengths as short as ∼6200 Å (77 °K). From the different spectral behavior of two separately photopumped epitaxial AlxGa1−xAs (x∼0.36) confining layers (1 and 0.3 μm thick) with an 80-Å (and a comparison 200-Å) GaAs quantum-well center layer, the recombination of hot electrons with holes collected in the quantum layer is used to estimate ΔEv.
Multiple fiber end fire coupling with single-mode channel waveguides
Authors: Hsu H. P. , Milton A. F. , Burns W. K.
Published: February 2003

We demonstrate a practical four-port flip chip end fire coupler useful for providing efficient coupling between single-mode fibers and Ti-diffused LiNbO3 channel waveguides. Channel waveguide ends were prepared for coupling by cleavage. With a configuration suitable for multiple fiber coupling, coupling efficiencies up to 47% have been measured for TM polarization. Using micropositioners to align single input and output fibers with respect to the channel waveguide, end fire coupling efficiency was 58% (TM). The effect of waveguide mode mismatch and misalignment on coupling efficiency is investigated. We also observe double refraction and leaky mode propagation with TE polarized input to LiNbO3 channel waveguides running perpendicular to the cleavage plane. With suitably prepared channel waveguides on LiTaO3, these effects are small or absent.
Optical surface waves along a toroidal metallic guide
Authors: Marhic M. E. , Kwan L. I. , Epstein M.
Published: February 2003

An approximate analysis shows that rays guided inside a torus oscillate sinusoidally around the equator. Expressing the Helmholtz equation in toroidal coordinates yields the equivalent index of refraction. The equation can be solved, yielding Airy functions in the direction perpendicular to the surface. Along the surface the equation is similar to that for media with a quadratic index profile, the Hermite-Gaussian solutions of which follow sinusoidal trajectories while oscillating in width. Experimental verification of these features is presented.
Prism-waveguide coupling efficiency for waveguides with an arbitrary refractive-index profile
Authors: Sarid Dror , Kermisch Dorian
Published: February 2003

Using the WKB approximation, we generalize Ulrich’s solution to the optimum coupling efficiency of a prism-waveguide coupler, so that it can be applied to a waveguide with an arbitrary refractive-index profile. As an example, we give an analytic solution to a waveguide having an exponential refractive-index profile.
A method of measuring the low tilt bias angle of liquid crystals
Authors: Suzuki K. , Toriyama K. , Fukuhara A.
Published: February 2003

A new method of measuring the low tilt bias angles of liquid-crystal displays is proposed. It is based on the threshold characteristics of magnetocapacitance, which vary according to the relative direction of the magnetic field and the directors. The tilt bias angle is determined completely by geometrical configurations and without any fitting procedure. The method ensures accuracy up to 0.1° in the present example. Threshold field variations due to sample rotation in the magnetic field are calculated from the theoretical magnetocapacitive curves, and experimental results are in good agreement with them.
An analysis of Compton scattering from planar channeled positrons
Authors: Pantell R. H.
Published: February 2003

The cross section for Compton scattering can be appreciably enhanced if energy is conserved in the initial to intermediate state transition. This resonance condition cannot be satisfied for a free particle, but it can be met if the particle is in a static electric or magnetic field. In this paper an analysis is presented for light scattering from relativistic particles in an electrostatic potential. Planar channeled positrons are used as the example. It is possible to achieve a large frequency upshift from the incident to the scattered radiation, with a cross section that is many orders of magnitude larger than the usual Compton cross section.
Light-induced motion of misfit dislocations in Ga1−xAlxAs1−yPy- GaAs heterojunctions
Authors: Fujiwara Takao , Imai Hajime , Takagi Nobuyuki , Takusagawa Masahito
Published: February 2003

Misfit dislocations aligned along the 〈11̄0〉 direction in Ga1−xAlxAs1−yPy-GaAs heterojunctions are shown to be moved by light irradiation. The motion of the misfit dislocation was observed with photoluminescence topographs and x-ray topographs. The velocity of the misfit dislocation is very rapid and proportional to the excitation-light intensity; it is about 2.5 μm/sec per excitation-light intensity of 100 W/cm2 at 25 °C. Its activation energy for the misfit dislocation motion is estimated to be about 0.26 eV. The rapid velocity and the low activation energy suggest that the misfit dislocations in Ga1−xAlxAs1−yPy-GaAs heterojunctions may move in the glide motion of the kink segments in it.
Effect of native oxide on the interface property of GaAs MIS structures
Authors: Suzuki Norio , Hariu T. , Shibata Y.
Published: February 2003

Interface native oxide has been found to cause anomalous frequency dispersion of capacitance in the accumulation region of n-GaAs MIS structures. Sputter etching by nitrogen is effective to remove the native oxide layer and obtain normal C-V characteristics by probably reducing surface-state density. The present results indicate that native oxide would not be essentially suitable for passivation of GaAs with low surface-state density.
An alternative theory of thermal dielectric relaxation in MIM structures
Authors: Gupta H. M.
Published: February 2003

The theory of thermal dielectric relaxation in MIM structures as proposed by Simmons and Taylor, considering growth of the ’’cathode depletion region’’, does not quantitatively agree with the experimental results. We therefore proposed a new model of thermal dielectric relaxation considering (i) thermal emission of surface traps within a small distance l (≈102 Å) from the interface and (ii) the recombination probability of emitted electrons. The agreement between theoretical and experimental results is satisfactory.
Measurements of compressed core density of laser-imploded targets by x-ray continuum-edge shift
Authors: Lee C. M. , Hauer A.
Published: February 2003

The density of the compressed neon core in laser-imploded neon-filled microballoons was measured by the shift to longer wavelengths of the free-bound x-ray continuum edges due to the recombination processes e−+Ne+9 and e−+Ne+10. The results are shown to be in good agreement with those obtained by fitting Stark profiles to neon x-ray lines. Density measurements based on continua will be particularly important at higher densities where most spectral lines of the neon ion would disappear due to pressure ionization.
Beam scanning with twin-stripe injection lasers
Authors: Scifres D. R. , Streifer W. , Burnham R. D.
Published: February 2003

Angular scanning of the far-field intensity peak of a GaAs/GaAlAs DH injection laser is demonstrated. This scan is accomplished by adjusting the current levels between two closely space stripe contacts, thereby creating an asymmetric gain/refractive index profile through which the laser beam propagates. Thus, this effect is somewhat analogous to passing the laser beam through a wedge. A deflection of the peak laser beam intensity of ±14° along the p-n junction plane is observed.
An iron-vapor laser
Authors: Linevsky M. J. , Karras T. W.
Published: February 2003

An iron-vapor laser has been demonstrated with emission in the blue at 4529 Å. Pulses of 6 nsec FWHM and peak power of 1 kW were produced. To our knowledge, this is the first such report and is at variance with previous expectations.
Extrema of electron density and output pulse energy in a CuCl/Ne discharge and a Cu/CuCl double-pulsed laser
Authors: Kushner M. J. , Culick F. E. C.
Published: February 2003

Electron-density measurements have been made in a CuCl/Ne discharge using a CO2 laser interferometer. A local maximum followed by a local minimum in electron density have been found to move a higher tube temperature with higher buffer pressure. Extrema in Cu/CuCl double-pulsed laser energy may be correlated with the extrema in electron density. An analysis based on rate equations yields qualitative agreement with measured laser-pulse energies. The results support the idea that ionization of copper is primarily responsible for the decrease of laser output as the tube temperature is increased.
Fourier-transform photoacoustic spectroscopy
Authors: Farrow Michael M. , Burnham Roger K. , Eyring Edward M.
Published: February 2003

Visible-light Fourier-transform photoacoustic spectroscopy (FTPAS) of Nd : glass is reported. The combined throughput and multiplex advantages of the interferometer significantly reduce the data collection time and/or improve the signal-to-noise ratio.
Low-threshold continuous laser operation (300–337 °K) of multilayer MO-CVD AlxGa1−xAs-GaAs quantum-well heterostructures
Authors: Holonyak N. , Kolbas R. M. , Laidig W. D. , Vojak B. A. , Dupuis R. D. , Dapkus P. D.
Published: February 2003

Data are presented on multilayer AlxGa1−xAs-GaAs quantum-well heterostructures showing that cw 300–337 °K laser operation is possible at photoexcitation threshold levels (≲1.2×103 W/cm2, Jth≲500 A/cm2) comparable to better LPE double heterojunctions and much lower than all previous single or multiple quantum-well heterostructures. These quantum-well heterostructures are grown by metalorganic chemical vapor deposition (MO-CVD) and consist of four 80–90-Å GaAs active layers coupled by three 80–90-Å AlxGa1−xAs (x∼0.35) barriers, all of which are sandwiched between 1- and 0.3-μm AlxGa1−xAs (x∼0.40) confining layers.
Photocollection efficiency and interface charges of MBE-grown abrupt p (GaAs) -N (Al0.33Ga0.67As) heterojunctions
Authors: Kroemer H. , Chien Wu.Yi , Casey H. C. , Cho A. Y.
Published: February 2003

The photocollection efficiency of abrupt p (GaAs) -N (AlxGa1−xAs) heterojunctions is found to be far too large to be compatible with the unmodified Shockley-Anderson model. The results are interpreted by postulating a positive interface charge density σ≃6×1011 cm−2.
GaAlAs diode sources for laser-Doppler anemometry
Authors: Shaughnessy E. J. , Zu’bi F. H.
Published: February 2003

A laser-Doppler anemometer based on a continuous GaAlAs diode laser source is described. It is shown that the coherence length of the diode output requires that the optical design incorporate equal path lengths for good fringe visibility. The results show that Doppler signals of processable quality may be obtained using this compact laser source.
Electrochemichromic cells based on phosphotungstic acid
Authors: Tell B. , Wagner Sigurd
Published: February 2003

We report a new material for self-contained all-solid-state electrochromic devices with fast response. The material is phosphotungstic acid (PWA) which, at room temperature, is both an electrochromic material and an ionic conductor. Response times of 50 msec have been measured in cells of type M/PWA/SnO2, where M denotes an electrode that provides ions of Ag, Cu, or Li. The cell exhibits memory.
Measurements of the ion-expansion structure and velocities from thin-foil laser-target interactions
Authors: Gusinow M. A. , Anthes J. P. , Matzen M. K. , Woodall D.
Published: February 2003

Energetic 8-nsec laser pulses were focused on Al, Au, and Cu foils ranging in thickness from 0.1 to 9 μm. The transmitted laser light was recorded and the plasma expansion from the front and back surfaces of these foils was measured using Thomson parabola and Faraday cup diagnostics. Comparison of the front- and back-surface Thomson parabola traces clearly shows the change from ablatively driven behavior to nearly symmetric exploding-pusher behavior for all of the materials.
An emulsion dye laser
Authors: Matheson Kenneth Lee , Thorne James M.
Published: February 2003

A laser dye which is insoluble in water has been dissolved in hexane and emulsified in a water matrix. When pumped with a nitrogen laser, this mixture was observed to lase. The emulsion is superior to a simple hexane solution because the excellent thermo-optical properties of the water matrix help prevent refractive-index gradients from degrading laser performance. This is a useful characteristic for flash-pumped dye lasers, laser-pumped dye lasers, and liquid filters. Another type of solvent system, a critical solution, is also discussed. For certain dyes, a critical solution has even better thermo-optical properties because of its ability to absorb heat as it undergoes a liquid-liquid phase transition.
Generation of time-reversed wave fronts using a resonantly enhanced electronic nonlinearity
Authors: Grischkowsky D. , Shiren N. S. , Bennett R. J.
Published: February 2003

Time-reversed optical wave fronts were generated by degenerate four-wave mixing in rubidium vapor. An extremely large and resonantly enhanced electronic nonlinearity, described by the adiabatic following (AF) model, was responsible for the mixing. The intensity dependence of the AF nonlinear susceptibility was shown to explain the observed reduction in conversion efficiency at high pumping intensities.
Self-contained integrated bistable optical devices
Authors: Smith P. W. , Kaminow I. P. , Maloney P. J. , Stulz L. W.
Published: February 2003

We have built self-contained bistable optical devices using integrated Fabry-Perot resonators formed by attaching dielectric mirrors to the cleaved ends of a LiNbO3 substrate containing a Ti in-diffused waveguide modulator. Feedback from a novel composite photovoltaic detector which samples the output beam is applied to the modulator electrodes. We also describe an off-axis extraordinary wave resonator which permits low-energy operation. These integrated bistable devices operate solely with optical inputs and outputs; no source of electrical energy is required.
Improvement of crystalline quality of epitaxial Si layers by ion-implantation techniques
Authors: Lau S. S. , Matteson S. , Mayer J. W. , Revesz P. , Gyulai J. , Roth J. , Sigmon T. W. , Cass T.
Published: February 2003

We demonstrate that the crystalline quality of Si layers grown on sapphire substrate (SOS) by the CVD method can be greatly improved through the use of implantation of Si ions and subsequent thermal annealing at relatively low temperatures (∼550 °C). This method utilizes an amorphous layer created by ion implantation near the sapphire/Si interface. Subsequent regrowth of this amorphous layer starting from the relatively perfect Si surface region leads to a much improved Si crystalline layer, as evidenced by MeV 4He+ channeling and TEM measurements. When the implantation-formed amorphous layer is located at the outer portion of the Si layer, thermal annealing leads to only a small reduction in the amount of defects in the regrown layer as compared to the unimplanted sample. In these layers, epitaxial regrowth occurs with the same rate and activation energy observed in self-ion-implanted 〈100〉 Si.
Consecutive microsecond pulsed ion beams from a reflex tetrode ion source
Authors: Wessel Frank , Robertson Scott
Published: February 2003

We have obtained two consecutive ion pulses separated in time by 2.6 msec from a long-pulse (1–2 μsec) reflex tetrode ion source. The source voltage is 100 kV and the ion current density is 0.7 A/cm2. Calorimetry indicates that the energy in two pulses is equal to 180% of that in the first pulse for delays of ≳2.6 msec. For shorter delays the energy in the second pulse is reduced due to premature shorting of the diode.
Influence of the absorption coefficient in Nd laser annealing of amorphized semiconductor layers
Authors: von Allmen M. , Lüthy W. , Thomas J. P. , Fallavier M. , Mackowski J. M. , Kirsch R. , Nicolet M-A. , Roulet M. E.
Published: February 2003

It is shown that epitaxial regrowth of thin amorphized Si layers by Nd-laser irradiation is strongly affected by temperature-induced changes in the absorptivity of the crystalline substrates. This results in an amplification of small spatial variations of the absorbed intensity by local thermal runaway. The problem can be avoided by either preheating the sample or by applying pulses of long duration and reduced intensity. A model explaining the observations is proposed.
MIS structures based on spin-on SiO2 on GaAs
Authors: Ma T. P. , Miyauchi K.
Published: February 2003

MIS capacitors have been produced on GaAs substrates using spin-on SiO2 as the primary gate insulator. Following appropriate densification and annealing procedures, these samples show electrical properties superior, or comparable, to the reported data on other GaAs MIS structures. The formation of the surface inversion layer in the reverse-bias region, the relatively low leakage current, and the small hysteresis in these samples strongly suggest that it may be possible to fabricate useful enhancement mode MOSFET’s on GaAs using the present technique. A detailed description of the experimental technique is presented along with a discussion of several considerations that led to the development of the technique.
The influence of growth-solution dopants on distribution coefficients in the LPE growth of InGaAsP
Authors: Feng M. , Tashima M. M. , Cook L. W. , Milano R. A. , Stillman G. E.
Published: February 2003

In experiments on the growth of InGaAsP alloys by liquid-phase epitaxy on (100) -InP substrates, it has been found that doping the growth solution with Zn, Sn, or Te causes changes in the epilayer lattice constant that results from changes in alloy composition. For growth from an In0.95707Ga0.0040As0.0353P0.00363 solution, the changes in the distribution coefficients of Ga and As due to doping have been found by comparing the compositions of epilayers grown either from an undoped solution or from solutions each doped with one of the three impurities. The epilayer compositions were determined by electron microprobe, the lattice constants were obtained by x-ray diffraction, and the energy gaps were estimated from transmission measurements.
A two-junction cascade solar-cell structure
Authors: Bedair S. M. , Lamorte M. F. , Hauser J. R.
Published: February 2003

A two-junction cascade solar-cell structure has been demonstrated in the AlGaAs/GaAs materials system. The cell consists of two p-n junctions with different band gaps monolithically connected in series by means of a low-resistance p-n junction. An open-circuit voltage of 2.0 V has been observed for this cascade structure. This is the highest open-circuit voltage that has been reported for a single monolithic photovoltaic cell.
Oscillations in the emf of solid-state electrochemical oxygen sensors
Authors: Hetrick R. E. , Logothetis E. M.
Published: February 2003

Oscillations have been found in the emf of ZrO2 electrochemical cells used for high-temperature oxygen sensing in nonequilibrium CO,O2 environments. This behavior is shown to arise from an oscillation in the platinum-catalyzed oxidation of CO. The use of a ZrO2 cell provides a new technique for studying oscillating reactions of this type.
Tl3AsSe3 noncollinear acousto-optic filter operation at 10 μm
Authors: Feichtner J. D. , Gottlieb M. , Conroy J. J.
Published: February 2003

An infrared tunable acousto-optic filter based on Tl3AsSe3 in a noncollinear configuration is described. The filter was operated at CO2 laser wavelengths from 10.8 to 9.3 μm, with corresponding rf drive frequencies in the 15–18-MHz range. Filter bandwidths are of the order of 20–30 cm−1, and the measured tuning rate is 18.0 kHz/cm−1 at 10 μm.
Intense 3371-Å laser emission from a fast Blumlein discharge excited N2/F2 mixture
Authors: Sumida Shin , Obara Minoru , Fujioka Tomoo
Published: February 2003

By adding a small quantity of F2, the 3371-Å (C3πu→B3πg second positive system) N2 laser energy in the fast Blumlein discharge was increased 30% over that for N2 alone. This value was obtained for a gas mixture of 4% added F2 and 96% N2 at a total pressure of 120 Torr.
Backside-illuminated HgCdTe/CdTe photodiodes
Authors: Lanir M. , Wang C. C. , Vanderwyck A. H. B.
Published: February 2003

This letter reports the first realization of backside-illuminated HgCdTe/CdTe photodiodes prepared by a liquid-phase-epitaxy technique. The thermal noise of these diodes is lower than that of bulk HgCdTe diodes fabricated under otherwise similar conditions. This is explained by an analytical model based on material parameters and the geometry of n+-p diodes.
Donor-levels analysis in GaAlAs double heterostructure
Authors: Balland B. , Vincent G. , Bois D. , Hirtz P.
Published: February 2003

Capacitance versus temperature, capacitance, and current DLTS, together with optical excitation, are used to analyze the donors in the n-type Sn-doped GaAlAs layer of LED double heterostructures. Two donor levels are found to be associated with Sn. One of them shows a persistent photoconductivity effect at low temperature.
Susceptibility measurements on the ion-implanted layer of bubble garnet films
Authors: Maartense I. , Searle C. W.
Published: February 2003

Measurements in the plane of bubble films show a sharp maximum in the ac susceptibility of implanted layers when the underlying film is saturated. The nature of this peak and its behavior as a function of bias field and etching carry information about the layer’s uniformity and anisotropy as well as the film’s domain collapse and stripe propagation fields and coercivity.
Stimulated electronic Raman scatterng from the 6s 2S1/2 to the 5d 2D5/2 state of cesium
Authors: Hodgson R. T.
Published: February 2003

The Raman transition 6s 2S1/2-5d 2D5/2 in atomic cesium was stimulated to emit at 2.38 μ by light at 532 nm from a frequency-doubled Nd : YAG laser. With 2 mJ energy in a 10-ns single-mode pulse of green light, a quantum efficiency of 7% for conversion to the infrared light was measured. No tunable infrared stimulated Raman emission could be generated with as much as 7 mJ energy from a multimode dye laser tuned around 601 nm.
The fabrication of Schottky-barrier solar cells by electroless nickel plating
Authors: Lue Juh Tzeng
Published: February 2003

Fabrication of Schottky-barrier solar cells by electroless nickel plating can be recognized as a practical approach because cells made by this method are of lower cost, have good adhesion to the surface, higher barrier potential height, and lower reflectivity of light as compared with those of the vacuum-evaporated devices. No expensive equipment, such as a vacuum evaporator or high-temperature diffusion oven, is needed for this manufacture.
Residual stacking-fault-type contrast in silicon after apparent unfaulting reactions
Authors: Tan T. Y.
Published: February 2003

Faint residual fringe contrast was observed in some regions of stacking faults (SF) in Si for which unfaulting reactions had apparently occurred. This phenomenon is attributed to an error which occurred in the apparent unfaulting process. Such an error produces, for the simplest case, a four-atom-layer-thick region on the {111} which was twinned and may also be regarded as normal {111} layers of matrix material containing an intrinsic-extrinsic SF pair. Thus, no normal SF contrast was observed; instead, the small twin boundary dilations produced the SF-like faint fringe contrast. Twin reflections were observed from such material regions.
High optical power density emission from a ’’window-stripe’’ AlGaAs double-heterostructure laser
Authors: Yonezu H. , Sakuma I. , Kamejima T. , Ueno M. , Iwamoto K. , Hino I. , Hayashi I.
Published: February 2003

Extremely high optical power density emission (107 W/cm2) was achieved with a new Zn-diffused ’’window-stripe’’ laser by eliminating the restriction of the catastrophic optical mirror damage (COMD). The maximum available optical power was at least one order of magnitude higher than the COMD threshold in conventional structures. Furthermore, gradual degradation due to the mirror oxidation has been reduced significantly under cw operation.
Electrical characteristics of the plasma-grown native-oxide/GaAs interface
Authors: Mimura T. , Yokoyama N. , Fukuta M.
Published: February 2003

Some basic features of the electronic properties of the plasma-grown native-oxide/GaAs interface have been investigated using transient current measurements on MOSFET structures. One of the most striking results is that injection and subsequent trapping in the native oxide is the mechanism responsible for a reduction in the amount of conduction electrons induced at the interface. The initial phase of stored electron decay is due to backtunneling from electron-trapping centers in the particular oxide region near the interface. The final phase of decay is caused by detrapping from a 0.60-eV Frenkel-Poole center in the oxide bulk.
Saturable absorption effects in the self-pulsing (AlGa)As junction laser
Authors: Paoli Thomas L.
Published: February 2003

The steady-state rate equations for a junction laser containing a saturable optical loss are analyzed in terms of parameters typical of contemporaory stripe-geometry (AlGa)As lasers. The analysis reveals that under conditions which produce self-induced intensity pulsations the steady-state power output may also exhibit a bistability or hysteresis over a small range of current in the vicinity of threshold. Experimental observations made with (AlGa)As double-heterostructure lasers reveal that a nearly discontinuous behavior in the laser’s output characteristic is, in fact, sometimes associated with the self-induced pulsations.