bluuebunny/crossref_metadata_2025 huggingface dataset:
On the controversy about the direction of electrotransport in thin gold films
Authors: Hummel R. E. , DeHoff R. T.
Published: February 2003

Annealed ’’pure’’ gold films exhibit electromigration against the electron flow. In contrast, gold films deposited on a transition metal underlayer show mass flow in the same direction as the electron flow. Diffusion of the transition metal from the underlayer into the gold film, deduced from Auger analyses presented herein, is believed to be responsible for this reversal. A new experiment, utilizing an ’’inverted temperature profile’’ gives unambiguous results on the direction of electrotransport.
Some second-phase structures in gallium arsenide annealed after implantation with zinc
Authors: Benson R. B. , Littlejohn M. A. , Pao P. S. , Sarin H. K.
Published: February 2003

After GaAs was implanted with 1015/cm2 60-keV Zn ions at ambient temperature, annealing with a rf-sputtered SiO2 passivating layer resulted in the formation of the second-phase structures ZnGa2O4 at 800 °C and primarily Zn3As2 at 600 °C. Possible relationships between the second-phase structures and the electrical properties of the ion-implanted annealed regions are discussed.
Isotopic enrichment of SF6 in S34 by multiple absorption of CO2 laser radiation
Authors: Lyman John L. , Jensen Reed J. , Rink John , Robinson C. Paul , Rockwood Stephen D.
Published: February 2003

An increase in the ratio of S34/S32 of 3300% over its natural ratio has been obtained by irradiating SF6 in the presence of H2 with an intensely focused CO2 laser. The quantities of material separated are on the order of 100 μg.
Efficient CuInSe2/CdS solar cells
Authors: Shay J. L. , Wagner Sigurd , Kasper H. M.
Published: February 2003

We report the preparation of a CuInSe2/CdS heterojunction solar cell having a solar power conversion efficiency of 12% measured on a clear day in New Jersey (∼92-mW/cm2 solar intensity).
A 15% efficient antireflection-coated metal-oxide-semiconductor solar cell
Authors: Stirn R. J. , Yeh Y. C. M.
Published: February 2003

A new effect is being developed which significantly improves the conversion efficiency of antireflection-coated metal-oxide-semiconductor ‘AMOS’ solar cells. The effect, a marked increase in the open-circuit voltage, is produced by the addition of an oxide layer to the semiconductor. Cells using gold on n-type gallium arsenide have been made with efficiencies up to 15% in terrestrial sunlight. All processing steps are amenable to the use of low-cost polycrystalline films of GaAs in place of the single crystals now used.
Scaling of the helium-nitrogen charge transfer laser
Authors: Collins C. B. , Cunningham A. J.
Published: February 2003

The scaling to high powers of the nitrogen ion laser pumped by charge transfer from He+2 is reported. Intense emission has been found from three laser lines at 3914, 4278, and 4709 Å upon discharge of a fast-pulsed electron beam gun, APEX-1, into several atmospheres of a mixture of helium and nitrogen. Excitation current densities were 1.4 kA/cm2 at 1 MV over a 1×10-cm transverse geometry. The efficiency of the 4278-Å laser emission was found to be proportional to the total pressure raised to the 1.2 power. Outputs of 36 mJ have been obtained from the 16-cm3 working volume at 30-atm pressure and a peak efficiency of 1.6% relative to the energy lost by the electron beam in this radiating volume has been achieved.
Stokes pulse growth in transient stimulated Raman scattering
Authors: Lowdermilk W. H. , Kachen G. I.
Published: February 2003

Transient stimulated Raman scattering in H2 and SF6 gas was studied with the use of a high-speed streak camera. The results are found to be in excellent agreement with theoretical predictions.
Metallic superconducting Si and Ge produced by vapor quenching on Cu
Authors: Reale Carlo
Published: February 2003

Fine-grained Si and Ge overlays crystallized in a metastable fcc phase were obtained by vapor quenching at 4.2 K onto microcrystalline Cu films quench-condensed at the same temperature on glass substrates. Measurements of the electrical resistance show that in this abnormal form Si and Ge behave as metals and can become superconductors. On warming, the metallic state keeps up to a critical temperature at which the overlay breaks. The fracture may be attributed to the large increase in volume occurring when the fcc phase transforms to the normal diamond-type semiconducting structure.
Gain switching and Q spoiling of iodine laser with a shock wave
Authors: Ishii S. , Ahlborn B. , Curzon F. L.
Published: February 2003

The power output of an iodine laser has been increased and the half-width of the laser spike reduced by compressing the photolytically pumped laser gas with a shock wave. The deflection of the beam in the density gradient of the shock front Q spoils the laser cavity until the shock front has traversed the lasing volume.
Laser-excited photoluminescence of three-layer GaAs double-heterostructure laser material
Authors: Nash F. R. , Dixon R. W. , Barnes P. A. , Schumaker N. E.
Published: February 2003

The successful fabrication of high-quality DH GaAs lasers from a simplified three-layer structure is reported. A major asset of this structure is the transparency of its final layer to recombination radiation occurring in the active layer, thus permitting the use of nondestructive photoluminescent techniques for material evaluation prior to device fabrication. In the course of photoluminescence investigations on this material the additional important observation has been made that indirect excitation (in which photocarriers are generated in the top ternary layer) has significant advantages over direct excitation (in which photocarriers are generated directly in the active layer). These include (i) the direct measurement of Al concentrations in both upper layers, (ii) the measurements of the minority-carrier diffusion length in the upper layer, (iii) an easily obtained indication of taper in the thickness of the upper layer, and (iv) surprisingly effective excitation of the active layer. By combining direct and indirect excitation it is shown that a clearer understanding of the location and detrimental influences of defects in the GaAs laser structure may be obtained. For example, the width of the region of reduced luminescence associated with many defects is found to be very excitation dependent and is confirmed to arise from reduced active region luminescence. The photoluminescent excitation techniques described should be useful in the study of other heterostructure devices and material systems.
Trap saturation in silicon solar cells
Authors: Fabre E. , Mautref M. , Mircea A.
Published: February 2003

The spectral response of silicon solar cells has been studied under different conditions of excitation. The photocurrent variations are not linear with incident flux, and the minority-carrier diffusion length increases under solar illumination because of trap saturation. It is thus possible to fabricate efficient solar cells with a lower-quality material.
Electron and hole transport in CVD Si3N4 films
Authors: Yun Bob H.
Published: February 2003

This letter reports on the finding that holes are more mobile than electrons in chemically vapor deposited (CVD) Si3N4. MIS structures with Si3N4 films as the insulating layers are used in the experiments. Holes are shown to be electrically injected from the silicon into the insulator when the aluminum-gate electrode is pulsed negative, and electrons when pulsed positive, with subsequent trapping in the nitride. The centroid of the trapped-hole distribution, X̄h, and that of the trapped-electron distribution, X̄e, as functions of the voltage pulse amplitude and duration are measured. The ratio of X̄h/X̄e increases with the amplitude of the pulse and its duration, where the centroids are referenced from the injection source, and exceeds 3 when the hole distribution spans the entire nitride thickness. Data suggest that hole traps are perhaps shallower than electron traps, hence the enhanced hole conduction in the silicon nitride.
Implantation profiles of low-energy helium in niobium and the blistering mechanism
Authors: Behrisch R. , Bo/ttiger J. , Eckstein W. , Littmark U. , Roth J. , Scherzer B. M. U.
Published: February 2003

The depth profiles of 1.5–15-keV 3He ions implanted into a Nb single crystal at doses of 5×1016–7×1018/cm2 have been measured using the 3He  (d,p)  4He reaction. A comparison of the results with theoretical predictions for the range and the damage distribution of 3He in amorphous material shows reasonable agreement. Furthermore, the Deckeldicke (i.e., thickness of the covers of the blisters) was determined by Rutherford backscattering in double alignment. The results indicate that stress release rather than explosion of gas bubbles is the dominant mechanism in blister formation.
Cerenkov pulse dispersion in two low-loss fibers
Authors: Franks L. A. , Nelson M. A. , Davies T. J.
Published: February 2003

We have measured the material and mode dispersion of a 50-psec Cerenkov light pulse generated in 500-m lengths of low-loss graded and step-index Corning fibers. The initial 15.7-nsec full width at half-maximum (FWHM) transmitted pulse in the graded fiber was reduced to less than 2 nsec with narrow-band optical filtering. Parallel measurements in the step-index fiber gave a value of less than 4 nsec for an initial 16.3-nsec FWHM pulse. Fluorescence induced in the fiber by the electron radiation was less than 1% of the amplitude of the transmitted Cerenkov light in the graded fiber and approximately 2% in the step fiber.
X-ray topographic study of dark-spot defects in GaAs-Ga1−xAlxAs double-heterostructure wafers
Authors: Kishino Seigô , Nakashima Hisao , Ito Ryoichi , Nakada Osamu
Published: February 2003

Dark-spot defects (DSD) in a GaAs-Ga1−xAlxAs double-heterostructure (DH) wafer are studied by x-ray topography. Such DSD’s are one of the primary sources of the dark-line defects (DLD) that cause rapid degradation of GaAs-Ga1−xAlxAs DH lasers. By using x-ray topography almost all DSD’s observed by photoluminescence topography are correlated with dislocations in a GaAs substrate. In addition, it is observed that some dislocations in the substrate are not sources of DSD’s when the dislocation axes are nearly parallel to the surface of the substrate.
Radiation protection of fiber optic materials: Effect of cerium doping on the radiation-induced absorption
Authors: Friebele E. J.
Published: February 2003

High-numerical-aperature lead silicate and barium crown glass uncald fibers have been doped with cerium to decrease their radiation sensitivity. The radiation-induced optical loss in both the visible and near-infrared in these core materials has been studied as a function of time (10−3–104 sec) after pulsed irradiation and cerium concentration (0–1 wt%). It has been determined that cerium is effective in decreasing the loss at a given time and increasing the decay rate of absorption.
New oscillation phenomena in VO2 crystals
Authors: Taketa Yoshiaki , Kato Fumio , Nitta Masayoshi , Haradome Miyoshi
Published: February 2003

New oscillation phenomena in VO2 crystals were observed. The oscillation is generated in the temperature region of the crystal transition, and its voltage and frequency depend upon the ambient temperature. The waveform of the oscillation is a rectangular pulse.
Selective growth of metal-rich silicide of near-noble metals
Authors: Tu K. N.
Published: February 2003

Near-noble metals react with Si to form a metal-rich silicide at 100 to 200 °C. Growth of the silicide is selected by the criterion that diffusion of near-noble metal atoms to the silicide-silicon interface is needed in order to maintain a high interface mobility. Structure of the metal-rich silicide facilitates the diffusion. It has been postulated that high interface mobility can be achieved by transforming Si atoms at the interface from covalent bonding to metallic bonding and the transformation can be induced by forming metal interstitials in Si.
Crystallization of amorphous silicon films by Nd:YAG laser heating
Authors: Fan John C. C. , Zeiger H. J.
Published: February 2003

We have converted amorphous Si films into crystalline Si by heating with focused Nd:YAG laser radiation. The films were scanned by a focused laser beam and then studied by reflection electron microscopy and x-ray diffraction. These studies indicate that crystallite sizes as large as 25 μm were produced and suggest that a crystallization technique using a scanned laser beam focused to a slit image could be useful in preparing large-grain Si films for photovoltaic cells.
Simple technique for determination of centroid of nitride charge in MNOS structures
Authors: Maes H. , Van Overstraeten R. J.
Published: February 2003

A simple technique is proposed to determine the exact amount of charge in the nitride layer of MNOS structures and the centroid of its distribution throughout the layer. The technique is only significant for MNOS devices with a thick nitride layer. From experimental data it is shown, using this technique, that the charge is trapped deep into the nitride layer, to a depth depending on the initial nitride field.
Enhancement of Schottky solar cell efficiency above its semiempirical limit
Authors: Green Martin A.
Published: February 2003

Geometries are described for increasing the efficiency of Schottky solar cells above the theoretical limits recently calculated. The ultimate conversion efficiencies for the new cells are the same as for p-n junction devices. With present technology, improvements of over 50% above the old limits are possible.
Saturation of impurity photoconductivity in n-GaAs with intense YAG laser light
Authors: Celler G. K. , Mishra S. , Bray Ralph
Published: February 2003

We report the observation of saturation of impurity photoconductivity in semiconducting n-GaAs illuminated by a Q-switched Nd:YAG laser with light intensity up to 3.5 MW/cm2. From the saturation of conductivity we determined the concentration of defects to be ≈1016 cm−3. These form the well-known 1.2-eV absorption band and are presumably Ga vacancies. The curve of photoconductivity versus light intensity can be fitted with a simple model, which yields the electron recombination coefficient. The relation of the absorption band to nonlinear optical studies in GaAs at 1.06 μ is reviewed.
Proposed atomic mercury anti-Stokes frequency converter
Authors: Komine H. , Byer R. L.
Published: February 2003

We propose to use population stored in the radiatively trapped 6°P1° atomic mercury resonant level (1850 Å) for frequency conversion by an anti-Stokes or two-photon process. Inversion is with respect to the lower-lying 63P °0,1,2 levels which are assumed empty following selective quenching or rapid conversion to the mercury dimer. Photon conversion gains of 2.5×10−2 cm/MW for 1.06-μm and 8.7×10−5 cm/MW for 10.6-μm input wavelengths with corresponding 0.4157- and 0.9116-μm output wavelengths are calculated at a 1016-cm−3 inversion density.
Acoustic-surface-wave velocity decrease produced by ion implantation in lithium niobate
Authors: Hartemann P.
Published: February 2003

Ion implantation was found to reduce the velocity of an acoustic surface wave propagating in lithium niobate. This frequency-dependent decrease may be mainly attributed to a reduction of the effective electromechanical coupling coefficient as reported in this letter. The impedance of 138-MHz interdigital transducers deposited on implanted niobate substrates has been determined versus ion dose.
Dark-field and stereo viewing with the acoustic microscope
Authors: Bond W. L. , Cutler C. C. , Lemons R. A. , Quate C. F.
Published: February 2003

Images from the acoustic microscope can be recorded with increased clarity and additional detail if one uses an ’’off-axis’’ arrangement wherein the axis of the output lens is tilted with respect to the input lens. Also, stereograms have been recorded by canting the plane of the object. With a stereoscopic viewer, depth information becomes apparent and texture can be seen.
Simultaneous determination of the total content of boron and phosphorus in high-resistivity silicon by ir spectroscopy at low temperatures
Authors: Kolbesen B. O.
Published: February 2003

The simultaneous determination of the total concentrations of B and P in silicon (ρ≳50 Ω cm) by a simple ir-spectroscopic technique at low temperatures (≈15 K) is reported. In general, in partly compensated semiconductor crystals only the neutral centers, e.g., the difference ‖nA−nD‖ of the donors and acceptors present, contribute to the ir absorption spectrum. Through excitation with polychromatic light containing wavelengths which cause the fundamental band transition, the previoulsy ionized compensated donors or acceptors are neutralized by the mechanism of optical charge exchange and can quantitatively be observed in the absorption spectrum. The reliability of this method was checked by a comparison of the spectroscopically determined concentrations with those evaluated by four-point-probe measurements. A degree of compensation below 10% has been observed only for a small fraction of the samples with ρ≳50 Ω cm.
Structural investigation of cold-rolled metallic glasses using positron annihilation methods
Authors: Chen H. S. , Chuang S. Y.
Published: February 2003

The effect of cold rolling on the structure of a metallic glass Pd0.775Cu0.06Si0.165 and a crystalline Pd has been investigated using positron annihilation methods. Only slight change in both the positron lifetime and angular distribution upon cold rolling has been noted for the metallic glass. This is in strong contrast to a large change observed for the crystalline Pd. It is therefore concluded that cold rolling of the metallic glass induces no vacancylike defects. It is also suggested that the local atomic rearrangements during plastic deformation may lead to the densification of the metallic glass.
A laser velocimeter utilizing laser-induced fluorescence
Authors: Stevenson Warren H. , dos Santos Reginaldo , Mettler Stephen C.
Published: February 2003

Addition of a fluorescent dye to the liquid used for scattering particle production in a laser Doppler velocimeter can result in a number of practical advantages. An investigation of this concept has been carried out using various dyes and solvents to determine its potential and limitations. The term ’’fringe mode fluorescence velocimetry’’ is recommended to describe this technique.
Hole injection and transport in SiO2 films on Si
Authors: Weinberg Z. A.
Published: February 2003

Hole and electron transport in SiO2 films thermally grown on Si are observed by detecting the carrier arrival at the Si with a shallow junction detector. Carrier generation and injection near the Al-SiO2 interface are achieved by uv photons obtained from a Ne discharge. Following charging of an exposed SiO2 surface by negative ions from a corona discharge, we find large amounts of holes near the Si-SiO2 interface with a dependence on substrate crystallographic orientation. The film charges up to an average field of 14.5±0.5 MV/cm. These findings suggest an alternative mechanism to impact ionization for initiation of breakdown in MOS structures.
Ion source of high brightness using liquid metal
Authors: Krohn V. E. , Ringo G. R.
Published: February 2003

The beam from an EHD ion source using liquid gallium has been shown to have a brigtness of 0.9×105 A cm−2 sr−1 at 21 kV and an energy spread of 12 eV at 10-μA total current. The effective source diameter was 0.2 μm as imaged by a 2-cm-long Einzel lens with a 0.12-mm aperture. Cesium was significantly poorer and mercury much poorer than gallium.
Dynamic spectroscopy and subpicosecond pulse compression
Authors: Ippen E. P. , Shank C. V.
Published: February 2003

Picosecond pulses from a mode-locked cw dye laser have been compressed in time to produce pulses as short as a few tenths of a picosecond. Dynamic spectroscopic investigations of the laser pulses reveal temporal asymmetry and frequency chirping on a subpicosecond time scale.
Spectral absorptance at 3.8-μ wavelength for aluminum and pyroceram at elevated temperatures
Authors: Robin James E. , Nordin Paul
Published: February 2003

The results of experiments that measure the spectral emittance ελ (hence absorptance) at 3.8-μ wavelength for 6061 aluminum alloy and 9606 pyroceram at elevated temperatures are reported. ελ for 6061 aluminum was measured within the molten state over the surface temperature range of 1200–2100 °F. For 9606 pyroceram, ελ was measured between 1000 and 2000 °F. The data shows that for aluminum, ελ increases linearly with temperature from 0.138 at 1200 °F to 0.190 at 2100 °F. For pyroceram, ελ has an initial value of 0.91 at 1000 °F and slowly decreases to 0.68 at 2000 °F.
GaAs MESFET prepared by molecular beam epitaxy (MBE)
Authors: Cho A. Y. , Ch’en D. R.
Published: February 2003

GaAs metal-semiconductor field-effect transistors (MESFET) have been prepared by molecular-beam epitaxy. At 6 GHz a noise figure of 3 dB was obtained with a corresponding gain of 10 dB. The transconductance of the device was 28 mmhos and Fmax was approximately 35 GHz.
Electronically variable surface-acoustic-wave velocity and tunable SAW resonators
Authors: Cross Peter S. , Haydl William H. , Smith Robin S.
Published: February 2003

From measurements of shifts in the resonant frequency of SAW resonators, it has been observed that the SAW propagation velocity under an interdigital transducer varies continuously as a function of external resistive or capacitive loads. For Al on YZ LiNbO3 at 34 MHz, the velocity under a transducer can be varied over a 1.4% range. Resonators, using a transducer to control the cavity transit time, have been fabricated which are continuously tunable up to 60 kHz. Capacitances are found to be superior as tuning elements, owing to the severe degradation of the resonance caused by resistances.
High-efficiency KrF excimer laser
Authors: Bhaumik M. L. , Bradford R. S. , Ault E. R.
Published: February 2003

Efficient high-power laser emission has been observed at 249 nm from a KrF excimer laser obtained by an electron-beam-pumped mixture of Ar, Kr, and NF3 (1300:130:1) at a total pressure of 2.25 atm. An energy of 1.5 J was extracted in a 125-nsec (FWHM) pulse from a 100-cm3 volume, using a coaxial electron-beam laser. Laser efficiency was estimated to be nearly 15% based on energy deposition in the gas. Over-all electrical efficiency was ∼1%.
cw Brillouin laser
Authors: Hill K. O. , Kawasaki B. S. , Johnson D. C.
Published: February 2003

The observation of efficient continuous-wave Brillouin laser action in an optical-fiber ring resonator is reported. Internal laser conversion efficiencies of 50% and a Brillouin-shifted output of 20 mW have been achieved.
Improved efficiency of MIS-silicon solar cells by HF treatment of the oxide layer
Authors: Kipperman A. H. M. , Omar M. H.
Published: February 2003

Low-temperature processes, which can be used for MIS structures, are very applicable for polysilicon solar cells. An HF treatment of the insulating oxide layer in single-crystal MIS-silicon solar cells turned out to enhance the short-circuit current such that the AM1 efficiency appeared to be more than 10% without antireflection coating. A low surface recombination is indicated by the response to the blue part of the solar spectrum.
Low-loss optical fibers prepared by plasma-activated chemical vapor deposition (CVD)
Authors: Geittner P. , Küppers D. , Lydtin H.
Published: February 2003

A modified method for the preparation of low-loss optical fibers by means of chemical vapor deposition (CVD) techniques has been developed. In this method, a nonisothermal plasma is used to stimulate the reactions. Deposition of oxides then occurs only heterogeneously on the substrate. Results obtained by this method show optical losses well below 10 dB/km—having a minimum of 1.4 dB/km at a wavelength of 1050 nm—and a pulse dispersion of 0.8 ns/km.
Electronic states of KrF
Authors: Dunning Thom. H. , Hay P. Jeffrey
Published: February 2003

We report ab initio calculations on the electronic states of KrF arising from the Kr+F, Kr++F−, and Kr*+F separated atom limits. We conclude, in agreement with earlier assignments, that the observed laser transition is C (1/2) -X (1/2) (5.15 eV calculated, 5.00 eV observed). The calculated lifetime of the C (1/2) state is 6.5 ns. The ionic 2Π state was found to lie close to the ionic 2Σ+ state.
Characteristics of a linearly pumped laser oscillator-amplifier at 496 μm
Authors: Brown Fielding , Hislop Peter D. , Kronheim Steven R.
Published: February 2003

A linearly pumped methyl fluoride laser oscillator-amplifier is described which yields a peak power of 30 kW in a linewidth <60 MHz. Linear pumping results in nearly complete saturation of the FIR transition and consequently in relatively high photon conversion efficiency, which in the present case is 70% of its maximum theoretical value at operating pressures of 2–3 Torr. The present result indicates that MW-level peak power, such as required for plasma-ion scattering experiments, may be achieved using less than 140 MW of CO2 laser pumping power (<14 J in 100 nsec) in an amplifier less than 2 m long.
Modeling the KrF laser discharge
Authors: Jacob J. H. , Mangano J. A.
Published: February 2003

In this letter we describe modeling of an E-beam-controlled discharge operated in gas mixtures containing mainly argon with approximately 10% krypton and a few tenths of a percent fluorine. The discharge physics is dominated by electron impact ionization and excitation of the rare-gas metastables. The ionization of the metastables impacts the discharge stability directly while their excitation strongly affects the efficiency of pumping KrF*. Predictions of the model are compared with experimental results.
Double absorptions in aggregate-roughened silver surfaces
Authors: Tokarsky R. W. , Marton J. P.
Published: February 2003

The reflectivity from Ag surfaces, formed by overcoating Ag-aggregated films deposited on heated substrates, shows interesting double absorptions. They appear in two distinct regions, near and beyond 1 μm and at ∼0.35 μm. The former is discussed in terms of a dipole model of the rough surfaces within the Maxwell-Garnett aprroximation and the latter is proposed to be surface plasmon excitation.
Theory of nonresonant multistable optical devices
Authors: Felber F. S. , Marburger J. H.
Published: February 2003

We show that a Fabry-Perot interferometer filled with a Kerr medium has a multiple-valued transmission-intensity characteristic. ’’On’’ and ’’off’’ field for bistable operation are estimated, and a simple but accurate approximate theory is described.
Superconducting properties of Nb3(Sn1−xGax) by a solid-state diffusion process
Authors: Horigami O. , Luhman Thomas , Pande C. S. , Suenaga M.
Published: February 2003

Monofilament Nb3(Sn1−xGax) wires were made by heat treating composites consisting of pure Nb, (Nb–1 wt% Zr), or (Nb–0.7 wt% Ga) in various Cu-Sn-Ga alloys matrices. Superconducting critical temperatures Tc and critical current densities Jc(H), up to 18 T were measured for these wires. In several samples both Tc and high-field critical current densities for the Nb3(Sn1−xGax) compounds were found to exceed pure Nb3Sn. The upper critical field, Hc2, also appeared to be substantially higher than for similarly produced Nb3Sn.
Adequacy of classical inverse bremsstrahlung theory for low-temperature plasmas
Authors: Billman Kenneth W. , Stallcop James R.
Published: February 2003

Recent improvements in diagnostic and computation techniques have made it possible to conduct sensitive experiments on plasma heating and thermal conductivity. The adequacy of classical absorption theory for low-temperature (T<20 eV) subcritical density experiments is examined.
Three-dimensional pictorial transmission in optical fibers
Authors: Yariv Amnon
Published: February 2003

Modal phase dispersion limits image transmission in optical fibers to distances too short to be of general interest. A technique based on nonlinear optical mixing is described for modal phase equalization and recovery of a transmitted image.
Dynamics of coloration of amorphous electrochromic films of WO3 at low voltages
Authors: Crandall Richard S. , Faughnan Brian W.
Published: February 2003

Measurements of the time dependence of the coloration (formation of HxWO3) of amorphous films of WO3 are described and analyzed in terms of a barrier for current flow at the WO3-electrolyte interface. A novel feature is that as coloration proceeds, the chemical potential of hydrogen in the HxWO3 increases, opposing further coloration.
Piezoelectric surface wave scattering on a semi-infinite short-circuited surface
Authors: Cambiaggio E. , Cuozzo F. , Rivier E.
Published: February 2003

The scattering of a surface acoustic wave reaching a metallized surface region of a piezoelectric crystal is investigated by a numerical finite-difference method. The perturbation of the electric potential in the discontinuity neighborhood is shown, and the surface wave reflection is determined.
TE-TM mode conversion by interaction between elastic surface waves and a laser beam on a metal-diffused optical waveguide
Authors: Yamanouchi Kazuhiko , Higuchi Kanji , Shibayama Kimio
Published: February 2003

TEm-TMn mode conversion by electro-optic and acousto-optic effects in a metal-diffused optical waveguide is described theoretically. Elastic surface waves and laser beams propagate along the X axis on Y-cut LiNbO3 single crystals, i.e., interactions are collinear. We predict completely the TE1-TM1 mode conversion at an elastic surface wave power of 33 mW along an interaction length of 5 mm with a width of 1 mm.
High-performance solar cell material: n-AlAs/p-GaAs prepared by vapor phase epitaxy
Authors: Johnston W. D. , Callahan W. M.
Published: February 2003

Solar cells with measured sea level sunlight power conversion efficiencies of 13–18% and areas of several cm2 have been prepared by vapor phase epitaxial growth of n-AlAs on p-GaAs substrates. The cells are provided with an antireflective passivating anodically grown coating and have much improved stability in the laboratory atmosphere.
Magnetic domain observation of induced anisotropy around scratches in Mn-Zn ferrites using SEM
Authors: Kinoshita M. , Murayama T. , Shimizu R. , Ikuta T.
Published: February 2003

The (001) plane Mn-Zn single-crystal ferrite specimen was scratched by a pyramidal diamond at an interfacial angle of 120° along the [010] direction. Around the scratch groove, [100] domains were induced and enclosed with zigzag-shaped walls, on which they are bounded by the main sample domains in the [010] direction. These domains have fine structure and could result from the induced anisotropy of the inverse magnetostriction effect caused by the residual stress around the scratch groove.
CO2 TEA lasers sustained by metastable N2
Authors: Olbertz A. H. M. , Reits B. J.
Published: February 2003

Metastable N2 is able to ionize the low-ionization seed gas tri-n-propylamine. In this way the entire CO2 laser gas discharge can be sustained.
Compression of 100-psec laser pulses
Authors: Lehmberg R. H. , McMahon J. M.
Published: February 2003

Optical pulse compression using diffraction gratings has been demonstrated previously for ultrashort pulses (<20 psec). It has not been previously demonstrated for longer pulses because the chirp bandwidth required for a reasonable grating spacing was unattainable. In this letter we report the compression of a 100-psec pulse by a factor ⩾12, at a grating spacing of 23 m, and with an efficiency approaching the theoretical limits.
Optical filters using coupled light waves in mixed crystals
Authors: Laurenti J. P. , Rustagi K. C. , Rouzeyre M.
Published: February 2003

Coupling of polarized optical waves in wurtzite II-VI mixed crystals is studied. It is shown that these crystals provide narrow-band optical filters over a wide spectral range.
Mobile Si ions in Fe-doped LiNbO3 crystals
Authors: Williams B. F. , Burke W. J. , Staebler D. L.
Published: February 2003

A mobile ionic species fixes thick-phase holograms in Fe-doped LiNbO3 crystals at temperatures between 100 and 200 °C. Results are given which show that Si ions are mobile at 200 °C in these crystals.
Growth characteristics of GaAs-Ga1−xAlxAs structures fabricated by liquid-phase epitaxy over preferentially etched channels
Authors: Botez Dan , Tsang Won Tien , Wang Shyh
Published: February 2003

In this paper, we report our studies of the liquid-phase epitaxy of GaAs and Ga1−xAlxAs single- and double-layered structures over preferentially etched channels in GaAs substrates. Results obtained indicate that various optical waveguide structures providing lateral optical confinement can be fabricated by this etch-and-fill technique. Further, it is found that the filling of the channels is dictated by surface tension of the melt rather than by preferential growth. This growth characteristic lessens the dependence of the final profile of the grown layer on the initial etched profile and makes the etch-and-fill technique particularly suitable for the fabrication of optical bends.
High-power visible laser action in neutral atomic fluorine
Authors: Bigio Irving J. , Begley R. F.
Published: February 2003

Atomic fluorine is produced by dissociation of NF3 in a fast-pulsed electrical discharge in helium. High-power laser action is observed, with 70 kW on five lines near 7100 Å, all of which are assigned to electronic transitions in neutral atomic fluorine. Two of the laser lines are reported here for the first time. Some scalability appears possible for this laser, which already has proven to be an excellent pump source for infrared laser dyes.
Misfit dislocations in heteroepitaxial Si on sapphire
Authors: Abrahams M. S. , Buiocchi C. J. , Corboy J. F. , Cullen G. W.
Published: February 2003

Edge-type misfit dislocations have been observed near the original growth interface of heteroepitaxial (100) Si/(011̄2) sapphire. They were seen in Si islands existing prior to complete substrate coverage. The Si was deposited from the vapor phase at 1000 °C. The dislocations lie parallel to the [022] and [022̄] directions. The edge character of the dislocations was established by diffraction contrast experiments, and also from the fact that their spacing is twice that of the corresponding moiré fringes. Their misfit-relieving nature is implied from the fact that their spacing (36.9±6.0 Å) compares favorably with that calculated for almost total misfit relief (37 Å).
Dependence of bubble deflection angle on the orientation of an in-plane magnetic field
Authors: Beaulieu T. J. , Calhoun B. A.
Published: February 2003

The deflection angle χ between the bubble trajectory and the drive field gradient ∇Hz depends on the magnitude Hp and orientation φ of an applied in-plane magnetic field. A model based on the measured field-induced static elongation ε and the resulting dyadic form of the viscous drag predicts χ=χ0+(1/8) ε sin 2χ0+(3/2) ε cos χ0 cosφ sin(φ−χ0), where χ0 is the deflection angle for Hp=0. Good agreement with experiment was obtained in an epitaxial film of Eu0.65Y2.35Fe3.8Ga1.2O12 for Hp=40 Oe using a nominal drive across the bubble of ΔH≈2 Oe.
Efficient high-power CH3F amplifier for a 496-μm cavity laser
Authors: Drozdowicz Z. , Temkin R. J. , Button K. J. , Cohn D. R.
Published: February 2003

A CH3F amplifier has been constructed for use with a narrow-linewidth pulsed 496-μm CH3F cavity laser. The power conversion ratio of the amplifier, defined as the ratio of 496-μm power emitted to CO2 power absorbed, had a maximum value of (4.7±2.5) ×10−3 at a CH3F gas pressure of 0.1 Torr. The highest average power, 6±1 kW, was produced by the oscillator-amplifier laser system when the amplifier was run with a CH3F gas pressure of 0.9 Torr. At this pressure the power conversion ratio of the amplifier was (1.8±1.0) ×10−3. Analysis of the gain data yields values for the small-signal gain and saturation intensity as a function of CH3F gas pressure.
Dielectric constant and its temperature dependence for GaAs, CdTe, and ZnSe
Authors: Strzalkowski Ireneusz , Joshi Sharad , Crowell C. R.
Published: February 2003

The dielectric constants of GaAs, CdTe, and ZnSe and their temperature dependences were found from low-frequency capacitance measurements. From 100 to 300 °K the dielectric constants vary linearly with temperature. No electric field dependence was found up to 104 V/cm, nor frequency dependence between 20 Hz and 1 MHz. The dielectric constants extrapolated linearly to 0 °K are 12.35±0.09, 10.31±0.08, and 8.80±0.07 for GaAs, CdTe, and ZnSe, respectively. The temperature coefficients λ (≡ε (0)−1 dε/dt) are 2.01×10−4/°K, 2.27×10−4/°K, and 1.71×10−4/°K, respectively, with an accuracy of ±0.02×10−4/°K.
Injection-stimulated dislocation motion in semiconductors
Authors: Kimerling L. C. , Petroff P. , Leamy H. J.
Published: February 2003

Misfit dislocations introduced during LPE growth are shown to act as sinks for point defects introduced by 1-MeV electron bombardment in Ga1−xAlxAs1−yPy/GaAs p+n heterojunctions. Electron-beam-stimulated dislocation motion was observed directly with in situ TEM studies on previously bombarded material. SEM measurements have correlated beam-induced defect annealing with recombination-enhanced defect motion. These results suggest that dislocation networks, which are active in the dark-line-defect degradation mode of heterostructure lasers, may form by a climb mechanism which is activated by the injection-stimulated motion of point defects.
Stimulated electron tunneling in metal-barrier-metal structures due to surface plasmons
Authors: Siu D. P. , Jain R. K. , Gustafson T. K.
Published: February 2003

It is shown that electron tunneling can be stimulated by electron–plasmon–virtual photon interactions. Negative differential resistance exhibiting a threshold voltage and current density is expected for metal-barrier-metal structures.
Direct experimental observation of band-structure effects in GaPxAs1−x : N alloys by radiative lifetime measurements
Authors: Chevallier J. , Mariette H. , Diguet D. , Poiblaud G.
Published: February 2003

The decay time of the photoluminescence due to the recombination of excitons bound to nitrogen in GaPxAs1−x alloys (x≳0.55) at 4.2 °K has been studied by uv laser time-resolved spectroscopy. Using hydrogen implantation in order to reduce greatly the nonradiative lifetime of the samples, we show that the measured decay time is the radiative lifetime τxR of the bound excitons. Its variation with alloy composition is in good qualitative agreement with theoretical predictions. The observed decrease of τxR when the alloy becomes richer in GaAs is due to the modification of the recombination transition rate when the Γ band gets closer to the X band (band-structure effect).
Ultraviolet electroluminescence in AlN
Authors: Rutz R. F.
Published: February 2003

A method of growing single-crystal low-resistivity (∼103 Ω cm) n-type AlN is described in which dc ultraviolet electroluminescence is observed for the first time. The emission is in a broad band extending from 215 nm into the blue end of the visible spectrum. AlN grown on tungsten and sapphire substrates is contacted with Al and Nb. Light emission occurs in small spots near the negatively biased contact for currents of a few mA at voltages as low as 17 V, but typically in the range between 30 and 150 V. The external quantum efficiency is 6×10−6, and at constant current the light output is nearly independent of temperature up to several hundred degrees centigrade.
Motion of p-n junctions in CuInSe2
Authors: Tell B. , Wagner Sigurd , Bridenbaugh P. M.
Published: February 2003

We report the first p-n junction delineation and diffusion study in a ternary chalcopyrite-type semiconductor. p-n junctions were formed in Zn- or Cd-plated p-CuInSe2 by 5-min anneals at 200–450 °C. By means of angle lapping and staining techniques, junction depths xj varying from ∼1 μm to ∼130 μm were determined. These measurements yield the relationship lnxj (μm) =14.31−6900/T (K). The interdiffusion coefficient derived from xj is D (cm2/sec) =164 exp[−1.19 (eV)/kT]. The large preexponential term indicates concentrations or mobilities of point defects substantially above those of the related II-VI compounds.
InP epitaxial thin-film formation by planar reactive deposition
Authors: Fraas L. M. , Zanio K. , Shibata M.
Published: February 2003

Complete InP epitaxy on GaAs and twinned InP epitaxy on CdS were achieved below 390 °C by planar reactive deposition (PRD). In this technique, indium metal is evaporated from a planar source with an integral cavity into which PH3 gas is introduced and decomposed. The decomposition reaction products, P2 and H2, are emitted from within the source cavity through a perforated top plate and the combined In, P2, and H2 vapor stream on arrival at the substrate forms InP films. High-energy electron diffraction and SEM measurements show the crystallographic quality of the resultant films to be limited by the substrate quality.
Signal saturation effects in photoacoustic spectroscopy with applicability to solid and liquid samples
Authors: McClelland John F. , Kniseley Richard N.
Published: February 2003

A simple model of the interaction between the optical and thermal properties of the sample is shown to predict signal saturation in photoacoustic spectroscopy in excellent agreement with measurements on a methylene blue dye solution. The measured onset of signal saturation as a function of the absorption is accurately predicted by the model from the sample’s thermal properties. The effect of light reflection by the sample on the photoacoustic signal is discussed.
Electrical conduction in mixed Langmuir films
Authors: Iizima S. , Sugi M.
Published: February 2003

The conductivity of mixed Langmuir multilayer films of (Cd arachidate)x– (Cd palmitate)1−x has been measured as a function of the molar fraction x at liquid-nitrogen temperature. The conductivity decreases exponentially with increasing x or the weighted average of the chain lengths of the fatty acid salts. The results are explained by the hopping conduction model for the multilayer films associated with interface states.
Double-heterostructure PbSnTe lasers grown by molecular-beam epitaxy with cw operation up to 114 K
Authors: Walpole J. N. , Calawa A. R. , Harman T. C. , Groves S. H.
Published: February 2003

Double-heterostructure Pb1−xSnxTe lasers with active regions of Pb0.782Sn0.218Te have been grown by molecular-beam epitaxy which operate cw up to heat-sink temperatures of 114 K. Temperature tuning of the emission from 15.9 to 8.54 μm wavelength is obtained, with emission at 77 K near 11.5 μm. The current-voltage characteristics show an abrupt change in slope at threshold, indicating high incremental internal quantum efficiency.
Direct detection of the Josephson radiation emitted from superconducting thin-film microbridges
Authors: Pedersen N. F. , Soerensen O. H. , Mygind J. , Lindelof P. E. , Levinsen M. T. , Clark T. D.
Published: February 2003

We report direct measurements of the Josephson radiation emitted in X band from a superconducting thin-film microbridge coupled to a resonance cavity. Power is emitted if one of the harmonics of the Josephson frequency is in the bandwidth of the receiver. The maximum power emitted during our experiment was 10−13 W. The Josephson radiation could easily be detected at frequencies off resonance.
New precision technique for measuring the concentration versus depth of hydrogen in solids
Authors: Lanford W. A. , Trautvetter H. P. , Ziegler J. F. , Keller J.
Published: February 2003

A method for the measurement of the concentration of hydrogen versus depth in solids using the 1H+15N resonant nuclear reaction is discussed. This method has a typical depth resolution of 50–100 Å, can be used to a depth of several microns, and can measure hydrogen in concentrations of one part per thousand or greater.
New matrix effect in ion-excited x-ray elemental analysis
Authors: Hill K. W. , Knudson A. R. , Comas J.
Published: February 2003

Pure Al and Al0.5Ti0.5 targets were bombarded by Ar ions in the energy range 100 keV–3 MeV. For Ar energies between 260 keV and 1.25 MeV, it was found that the Al-Ti target is a more intense emitter of Al K x rays than is the pure Al target. These findings are consistent with the predictions of a two-step process in which Ar L-shell vacancies produced in an Ar-Ti collision are transferred to the K shell of an Al atom in a second collision.
Efficient lattice-matched double-heterostructure LED’s at 1.1 μm from GaxIn1−xAsyP1−y
Authors: Pearsall T. P. , Miller B. I. , Capik R. J. , Bachmann K. J.
Published: February 2003

The growth and operation of lattice-matched double-heterostructure InP/Ga0.17In0.83As0.34P0.66/InP light-emitting diodes is reported. These diodes have an emission wavelength of 1.1 μm and quantum efficiencies of 4%.
Multiple storage of holograms in an organic medium
Authors: Bartolini R. A. , Bloom A. , Escher J. S.
Published: February 2003

The multiple storage of volume phase holograms in samples of camphorquinone in an acrylic polyester is discussed.
Laser oscillation on the 292-nm band system of Br2
Authors: Murray J. R. , Swingle J. C. , Turner C. E.
Published: February 2003

Laser oscillation has been observed on numerous rotational transitions of the most intense bands of the Br2 emission system near 292 nm. The laser is electron-beam excited in an Ar-Br2 mixture. Quenching of the lower level by Br2 is inferred.
Domain pattern excited by surface acoustic waves in a nematic film
Authors: Miyano K. , Shen Y. R.
Published: February 2003

Periodic domain patterns have been generated by surface ultrasonic waves in a nematic liquid crystal film. Rotational vortex motion of the fluid due to acoustic streaming and the resultant shear flow alignment of the director are believed to be responsible for the observation.
58-MHz surface-acoustic-wave video intermediate-frequency filter using ZnO-sputtered film
Authors: Shiosaki T. , Ieki E. , Kawabata A.
Published: February 2003

The acoustic-surface-wave filter for the use of video intermediate frequency at 58 MHz was fabricated using an rf-sputtered ZnO film overlying the interdigital electrodes and the wave path on a glass substrate, and its fundamental properties for practical application were studied. The average and easily reproducible insertion loss characteristics are as follows: 16 dB at the minimum, 5(+16) dB at chromatic and picture signal carrier frequencies, 15(+16) dB at sound signal carrier frequency, more than 55(+16) dB at trap frequencies for adjacent channels, and 35(+16) dB at the maximum side lobe. The triple transit echo suppression is more than 30 dB. The temperature coefficient of the frequency characteristic is 30 ppm/°C. 400 days of aging has shown no significant change in the filter.
Strain dependence of electromagnetic generation of ultrasonic surface waves in ferrous metals
Authors: Thompson R. Bruce
Published: February 2003

It is demonstrated that the efficiency of the electromagnetic generation of ultrasonic surface waves in ferrous metals is strongly influenced by superimposed elastic strains. A graph of efficiency versus applied magnetic field has many features, and the changes of these in Armco iron and 1018 Steel are reported for the strain range −3×10−3 <Δl/l <3×10−3 (‖calculated stress‖<620 MN/m2 or 90 KSI). Striking changes are observed, particularly for fields below 200 Oe. The results are interpreted in terms of the strain dependence of the magnetostrictive properties of the material. Possible applications of the effect to nondestructively measure residual stress are considered.
Efficient electric discharge lasers in XeF and KrF
Authors: Burnham R. , Powell F. X. , Djeu N.
Published: February 2003

Laser action has been obtained in XeF and KrF in a transverse electric discharge powered by a fast Blumlein-type circuit. Over-all efficiencies of these lasers exceeded 1% for XeF and 0.3% for KrF. Maximum pulse energies of 100 mJ in XeF and 30 mJ in KrF were extracted. In XeF the peak pulse power was 25 MW while in KrF the peak pulse power was 1.5 MW.