bluuebunny/crossref_metadata_2025 huggingface dataset:
A simple method for fabricating lines of 0.15-μ width using optical lithography
Authors: Jelks E. C. , Kerber G. L. , Wilcox H. A.
Published: February 2003

A ’’shadow deposition’’ technique using only optical lithography and conventional thin-film technology has been used to fabricate titanium lines with nominal widths of 0.15–0.30 μ on glass substrates. Each of these lines was produced by evaporating metal at an angle to a photoresist edge and utilizing the region ’’shadowed’’ from the evaporating atoms by the edge to form an in situ mask of submicron dimensions with highly correlated edges. Uniformly wide lines having tapered edges and widths less than 0.1 μ appear to be reliably attainable with this technique. It is expected that the method will be useful for making Josephson junctions and other devices employing titanium, niobium, or any other material that can be vapor deposited.
Long-life operation of an XeCl excimer laser
Authors: Burlamacchi L. , Burlamacchi P. , Salimbeni R.
Published: February 2003

An experimental investigation of the performance of an XeCl excimer laser operating with moelcular traps is reported. The effects of cold traps, active carbon, and molecular sieves on the lasing gas mixture has been tested in order to selectively remove contaminant reaction products which quence laser action. Best results have been obtained by using a 3-Å molecular sieve directly inserted into the laser chamber. More than 180 000 shots have been obtained after 5 h of 10-Hz laser operation with a single refill before the output power decayed to one-half the initial value.
Efficient operation of a 100-W transverse-flow oxygen-iodine chemical laser
Authors: Benard D. J. , McDermott W. C. , Pchelkin N. R. , Bousek R. R.
Published: February 2003

Efficient extraction of chemically generated O2(1Δ) energy has been obtained in a trasverse-flow oxygen-iodine laser. The measured power extraction efficiency with off-optimal outcoupling was 15%. Output powers in excess of 100 W were obtained for periods of up to 3 min.
Improvements of ’’i
n s
i
t
u’’ multifilamentary Nb3Sn superconducting wires
Authors: Roberge R. , Foner S. , McNiff E. J. , Schwartz B. B. , Fihey J. L.
Published: February 2003

’’In situ’’ multifilamentary Nb3Sn wires with improved high-field properties are reported. An overall critical current density greater than 104 A/cm3 is achieved at 14 T for a Cu–36 wt%–Nb–20 wt% Sn material. The results are comparable to the best reported commercial multifilamentary Nb3Sn materials.
Fe-B-C amorphous alloys with room-temperature saturation induction over 17.5 kG
Authors: Hatta S. , Egami T. , Graham C. D.
Published: February 2003

Amorphous alloys of Fe86B14−xCx (5⩽x⩽7) were found to have room-temperature saturation induction approaching 18 kG after appropriate heat treatment. The alloys possess excellent soft-magnetic properties with the ac loss less than 0.5 W/kg at 17 kG and 60 Hz. It is expected that the application of these alloys to power transformers will produce very large savings of energy.
The crystal orientation dependence of multiplication noise in germanium avalanche photodiodes
Authors: Kaneda T. , Mikawa T. , Toyama Y. , Ando H.
Published: February 2003

We present the first study of multiplication noise for three orientations of electric field in germanium avalanche photodiodes (APD’s). The directional differences of noise are found to be rather weak by the measurements using a He-Ne laser (6328 Å). The differences obtained, 0.5 dB, were comparable in value to the experimental errors.
Capacitance measurements on organic-semiconductor Schottky barriers—A new approach
Authors: Popovic Zoran D.
Published: February 2003

Schottky-barrier parameters of an organic-semiconductor thin-film cell have been determined by a capacitor discharge method which is appropriate for systems where high resistance, trapping, and/or slow impurity ionization dynamics may prevent the use of conventional measurement techniques.
Thin-film GaAs solar cells with grain-boundary edge passivation
Authors: Ghandhi S. K. , Borrego J. M. , Reep D. , Hsu Y-S. , Pande K. P.
Published: February 2003

Solar cells built on polycrystalline gallium arsenide usually have very leaky reverse characteristics and low open circuit voltage. Both these problems arise from the effect of the Schottky diode made on the grain boundary, which shunts the active Schottky solar cell and deteriorates its performance characteristics. Selective anodization techniques have been used to provide an insuating barrier over the grain boundary in order to passivate it. Leakage current reduction of five to six decades has been achieved by this method. In this letter we describe the electrical and photovoltaic characteristics of devices made by this technique. We report, for the first time, a simulated AM1 conversion efficiency of 5.45% on thin-film (8.6 μm) polycrystalline GaAs cells with no antireflection coating, fabricated on molybdenum substrates by the simultaneous pyrolysis of trimethylgallium and arsine in hydrogen.
A simple high-performance current-switched Josephson gate
Authors: Fulton T. A. , Pei S. S. , Dunkleberger L. N.
Published: February 2003

A versatile current-switched gate is described which consists of two Josephson tunnel junctions and a small resistor in a loop. The directly combined bias and control currents flow through one junction in the zero-voltage state, causing the switching. The second junction and the resistor provide isolation between input and output after switching. The switching speed of a few tens of picoseconds and the microwatt power dissipation are comparable to those of other present designs. The design is particularly simple, compact, and easy to fabricate.
Arrays of superconducting tunnel junctions as low-noise 10-GHz mixers
Authors: Rudner S. , Claeson T.
Published: February 2003

Quasiparticle mixing (biasing at the gap voltage) was studied in arrays of small Pb-O-Pb tunnel junctions. Coherent mixing at 9 GHz gave a conversion loss as low as −5.8 dB and a single sideband mixer noise temperature of 10–40 K. The optimal conversion efficiency was obtained where the bias current microwave response was maximal. The arrays of junctions were rugged, and gave a good impedance match to external circuitry.
The effects of processing stresses on residual degradation in long-lived Ga1−xAlxAs lasers
Authors: Goodwin A. R. , Kirkby P. A. , Davies I. G. A. , Baulcomb R. S.
Published: February 2003

Oxide-insulated stripe-geometry double-heterostructure lasers have been lifetested continuously for periods up to 25 000 h. Degradation occurred in two stages, an initial stage lasting several thousand hours and a final stage, characterized by rates of threshold increase of 0–6 and 1–2%/kh, respectively. The dominant stress in these lasers is caused by the insulating oxide film. The magnitude of the stress was found to vary considerably depending on the detailed shape of the oxide profile and thickness. Good correlation was found between stress magnitude and initial residual degradation rate. It is concluded that for reliable laser performance processing stresses must not exceed 1×108 dyn cm−2 in the active region.
The CdTe/HgTe superlattice: Proposal for a new infrared material
Authors: Schulman J. N. , McGill T. C.
Published: February 2003

We propose a new material which could be useful in a number of infrared optoelectronic devices. The material consists of alternating (100) layers of CdTe and HgTe. The band gap of this superlattice is adjustable from 0 to 1.6 eV depending on the thicknesses of the CdTe and HgTe layers. Details of the band-gap variation and the character of the band-edge states are presented.
A SAW/CCD accumulating correlator
Authors: Smythe D. L. , Ralston R. W. , Stern E.
Published: February 2003

A new analog-signal-processing device is reported in which a charge-coupled device (CCD) is coupled to a piezoelectric surface acoustic wave (SAW) delay line across a 300-nm gap. The CCD samples multiply, accumulate, and read out the cross-correlation function of two wide-band SAW input signals which counterpropagate on the delay line. A signal-processing gain of 30 dB at a bandwidth of 20 MHz has been observed by correlating biphase modulated pseudonoise waveforms of 100-μs duration in the presence of Gaussian noise. This compact hybrid structure provides 300 discrete samples of a 7-μs segment of the correlation function.
Infrared-microwave double resonance of NH3 using a tunable diode laser
Authors: Takami Michio
Published: February 2003

Infrared-microwave (IR-MW) double resonance was demonstrated on the ν2 sQ (3,3) line of NH3 using a tunable diode laser. The laser beam was focused into a waveguide cell. The double-resonance effect was observed as a variation of infrared absorption when the J=K=3 inversion line of NH3 was saturated in the ground vibrational state. At low pressure the signal reversed its sign, indicating saturation of the infrared transition by the laser. Application of the technique to microwave spectroscopy of vibrationally excited molecules is discussed.
Increase in luminescence efficiency of AlxGa1−xAs grown by organometallic VPE
Authors: Stringfellow G. B. , Hom G.
Published: February 2003

A modification of the cold-wall organometallic vapor-phase epitaxial (OMVPE) process for the growth of AlxGa1−xAs layers is described. Graphite baffles placed in the gas stream act to greatly increase the photoluminescence efficiency of the AlxGa1−xAs. Preliminary evidence indicates that the effect of the baffles may be to provide a solid surface upon which Al2O3 can be deposited from the reaction of trimethylaluminum with any residual O2 and/or H2O in the vapor phase. The ’’gettering’’ action apparently reduces oxygen contamination of the AlxGa1−xAs.
Technique for profiling 1H with 2.5-MeV Van de Graaff accelerators
Authors: Doyle B. L. , Peercy P. S.
Published: February 2003

We describe an elastic recoil detection (ERD) analysis technique for profiling 1H in the near-surface regions of solids using a 2.5-MeV Van de Graaff accelerator commonly used for ion-backscattering analysis. Energy analysis of 1H forward scattered by 2.4-MeV 4He incident on the target tilted at an angle of ∼75° yields a depth resolution of ≲700 Å and a sensitivity of better than 0.1 at.% for 1H to depths of ≲0.6 μm in solids.
Arsenic incorporation in native oxides of GaAs grown thermally under arsenic trioxide vapor
Authors: Schwartz G. P. , Griffiths J. E. , DiStefano D. , Gualtieri G. J. , Schwartz B.
Published: February 2003

The presence of crystalline and amorphous elemental arsenic in films grown by the thermal oxidation of GaAs under arsenic trioxide vapor was observed using Raman backscattering. Arsenic was detected for all oxidation temperatures (350–500 °C) and resulting film thicknesses (∼80–1000 Å). Chemical etching demonstrated that the arsenic is retained in the interfacial region during growth and does not result from physical adsorption of gas-phase species during cooling.
Measurement of spatial distribution of long-wavelength radiation from GaAlAs injection lasers
Authors: Abbott S. M.
Published: February 2003

Present BTL injection lasers being produced for optical communication systems exhibit luminescence peaks at 1.5 eV (0.83 μm), 1.35 eV (0.92 μm) and 1.0 eV (1.25 μm). Examination of the spatial distribution of this radiation within the DH-laser diode has shown that the edge (1.5 eV) emission is confined to the active region, as expected, but the 1.35-eV radiation is divided between the active region and the substrate while the 1.0-eV radiation originates predominantly within the substrate. This result, in conjunction with recent work on laser aging, suggests that slow degradation of lasers may be due to a mobile impurity or defect originating in the substrate material on which the laser structure is fabricated.
Monolithic (ZnO) Sezawa-mode p
n-diode-array memory correlator
Authors: Lo F. C. , Gunshor R. L. , Pierret R. F.
Published: February 2003

The available bandwidth for a monolithic ZnO pn-diode memory correlator can be significantly increased by employing a thicker ZnO film which adapts the device to the Sezawa mode of operation. Herein we report the first Sezawa-mode pn-diode-array memory correlator and describe its operating characteristics. The device displays a 3-dB bandwidth of 20 MHz at a center frequency of 164 MHz; storage times are on the order of tens of milliseconds.
Stepped I-V characteristics of MIS capacitors in the inversion polarity
Authors: Davidoff S. , Kashat I. , Klein N.
Published: February 2003

The inversion-mode I-V characteristic of several kinds of MIS capacitors exhibits a step between steeply rising ranges at low and high voltages. It was found with silicon-dioxide–silicon-nitride capacitors on p-type silicon that current in the low-voltage range is determined by tunneling from the silicon into the insulator. In the step the current is determied by minority-carrier supply from the silicon and in the high-voltage range by avalanching in the silicon depletion layer and by tunneling into the insulator.
Simultaneous stimulated Raman scattering and optical frequency mixing in lithium iodate
Authors: Ammann E. O.
Published: February 2003

Efficient stimulated Raman scattering (SRS) has recently been achieved in lithium iodate (LiIO3) at kHz PRF’s, thereby producing substantial average output powers in the first and second Stokes lines. In this letter, we show that the same LiIO3 crystal that serves as the Raman medium can also be used to generate the second harmonics and sum frequencies of the pump and Stokes lines. By rotating a LiIO3 crystal placed inside a Nd : YAlO3 laser, we have successively generated phase-matched outputs at 0.54 μm (1.13 W), 0.565 μm (78 mW), 0.592 μm (685 mW), 0.622 μm (98 mW), and 0.655 μm (107 mW).
Atomic gallium photodissociation laser
Authors: Hemmati H. , Collins G. J.
Published: February 2003

Stimulated emission has been observed on the 417.2-nm line of neutral atomic gallium by photodissociation of gallium iodide molecules with the 193-nm output of an ArF laser. Laser output energies of 100 μJ per pulse were obtained from the absorption of 5 mJ of ArF laser radiation.
FM mode-locked Nd0.5La0.5P5O14 laser
Authors: Chinn S. R. , Zwicker W. K.
Published: February 2003

A FM mode-locked Nd0.5La0.5P5O14 laser excited by a cw dye laser has been constructed. The 1052-nm laser pulses, occurring at a 480-MHz repetition rate, had widths as short as 14 ps, determined by a correlation measurement. With appropriate detuning of the cavity round-trip interval, uniform amplitude FM output was obtained, with bandwidth up to 240 GHz.
Measurement of piezoelectric parameters versus bias field strength in polyvinylidene fluoride (PVF2)
Authors: Rezvani Behruz , Linvill John G.
Published: February 2003

Piezoelectric polymers, such as PVF2, being light and flexible, are attractive new materials for transducers. A new all-electrical meaurement method for piezoelectric parameters of PVF2 has been developed. Moreover, the method permits application of a variable bias field going to high values in addition to the small alternating field used for measurement. By using this technique, it has been found that linear performance extends to a very high electric field (30 V/μm) without degradation. This technique is also used to study the behavior of d31 under a range of dc field strengths. Finally, the method is used to investigated various procedures for poling PVF2.
Determination of the valence-band discontinuity of InP1−xGaxP1−zAsz (x∼0.13, z∼0.29) by quantum-well luminescence
Authors: Chin R. , Holonyak N. , Kirchoefer S. W. , Kolbas R. M. , Rezek E. A.
Published: February 2003

By means of liquid-phase epitaxy, undoped single-quantum-well layers of In1−xGaxP1−zAsz (x∼0.13, z∼0.29) of thickness Lz∼150 Å are grown embedded in InP and are examined in photoluminescence. Hot-electron recombination from Ec (InP) to bound holes in the quaternary quantum well leads to stimuated emission in a band ∼80 meV below Eg (InP) and thus to an estimate of ΔEv∼80 meV (ΔEc∼ΔEv) for the InP-InGaPAs valence-band discontinuity.
Picosecond laser-induced melting and resolidification morphology on Si
Authors: Liu P. L. , Yen R. , Bloembergen N. , Hodgson R. T.
Published: February 2003

Ultrafast melting and resolidification on the surface of a silicon crystal has been induced by picosecond laser pulses at 532 and 266 nm. Optical microscopy and electron diffraction revealed the formation of amorphous silicon. Details of surface morphology are sensitive functions of pulse intensity, energy, wavelength, and crystallographic orientation.
Shallow-junction p+-n germanium avalanche photodiodes (APD’s)
Authors: Kaneda T. , Fukuda H. , Mikawa T. , Banba Y. , Toyama Y. , Ando H.
Published: February 2003

Low-noise and high-quantum-efficiency germanium APD’s have been investigated by a p+-n structure. Boron implantation was used to form the p+ layer. Shallow p+-n junctions have a lower excess noise that n+-p junctions because holes have a higher ionization coefficient in germanium, and these p+-n diodes have a higher hole-to-electron collection efficiency. Excess noise factors F≈7 at a multiplication factor of 10 are obtained at wavelength of ∼1.4 μm, whereas F≈11 for n+-p diodes. An internal quantum efficiency of ∼80% is obtained at 1.15 μm.
A method for determining the region of superparamagnetism
Authors: Candela George A. , Haines Ruth A.
Published: February 2003

A simple procedure which determines the coercive force as a function of temperature has been developed for superparamagnetic materials having a particle-size distribution. This procedure accurately determines the region where superparamagnetism occurs, and it has been used to obtain the first experimental verification of the Bean-Livingston coercive-force temperature relation.
Unified weak-field magnetoresistance phenomenology for cubic and noncubic (001)- and (111)-oriented epitaxial films and surface layers
Authors: Allgaier R. S. , Restorff J. B. , Houston Bland
Published: February 2003

Extensions of the Seitz-Pearson-Suhl weak-field magnetoresistance (WFMR) formula are applied to cubic and noncubic (001) - and (111) -oriented epitaxial films and surface layers, including the extreme case of two-dimensional conductivity in a quantized layer. It is shown that four distinct WFMR measurements may be made on samples in either plane, thus providing a simple and reliable means of distinguishing cubic from noncubic transport environments.
Brillouin spectrum of single-mode optical fibers
Authors: Rowell N. L. , Thomas P. J. , van Driel H. M. , Stegeman G. I.
Published: February 2003

Experimental and theoretical results are presented for the Brillouin spectrum of single-mode optical fibers in the 180° scattering geometry. It is shown that for core diameters less than 10 μm both the Brillouin frequency shift and spontaneous linewidth are influenced by the nature of the normal acoustic-mode spectrum and wave-vector nonconservation in the acousto-optic interaction. The velocity and lifetime of longitudinal phonon excitations in the core are evaluated, and the consequences to stimulated Brillouin scattering assessed.
Laser-damage-resistant transparent conductive indium tin oxide coatings
Authors: Pawlewicz W. T. , Mann I. B. , Lowdermilk W. H. , Milam D.
Published: February 2003

Transparent conductive coatings of In1.9Sn0.1O3 have been made on fused silica which exhibit damage thresholds of 2.2 and 3.1 J/cm2 for 0.15- and 1-nsec Nd : glass laser pulses, respectively. The coatings were made by reactive sputtering in an rf diode system. Coating absorption detected spectrophotometrically was less than 1% (∼300 cm−1) near 1064 nm for coatings with in-plane resistivities of 0.017 and 0.55 Ω cm. An important potential application for such coatings is as the electrode for electro-optic shutters based on the longitudinal Pockels effect which are used in high-energy laser systems.
Angle-of-incidence effects in electron-beam-deposited SnO2/Si solar cells
Authors: Feng Tom , Ghosh Amal K. , Fishman Charles
Published: February 2003

The power-conversion efficiency of SnO2/Si solar cells fabricated by electron-beam evaporation of SnO2 is strongly dependent on the angle of incidence of the SnO2 vapor stream on silicon. The optimum angle of incidence is between 50° and 70°. Solar cells with power-conversion efficiencies exceeding 10% have been reproducibly fabricated by depositing the SnO2 at angles of incidence in this optimum range.
Temperature dependence of recombination rate constants for KrF*+R+R→RKrF*+R (R=Ar,Kr)
Authors: Shui Ven H.
Published: February 2003

The temperature dependence of recombination rate constants for KrF*+R+R→RKrF*+R (R=Ar,Kr) has been calculated by using the classical phase-space theory in the temperature range 300–800 °K. The steep (negative) temperature dependence obtained indicates the possibility of increasing the overall KrF* laser efficiency by raising the operating temperature.
Improvement in XeF laser efficiency at elevated temperatures
Authors: Hsia J. C. , Mangano J. A. , Jacob J. H. , Rokni M.
Published: February 2003

Improvement in e-beam-pumped XeF laser efficiency is reported when the laser is operated at temperatures above 300 °K. The improvement is due predominantly to improved energy extraction from the upper laser level as well as decreased lower level lifetime. The highest intrinsic laser efficiency (laser energy out/e-beam energy deposited in the active medium) observed at 3 amagats and 450 K is 5.5%. The temperature at which the highest efficiency is achieved is observed to increase with increasing gas density.
Pulsed transverse electrodeless discharge excitation of a CO2 laser
Authors: Christensen C. P.
Published: February 2003

A pulsed electric discharge between two dielectric sheets which is suitable for laser excitation is reported. CO2 laser operation at pressures extending to 650 Torr in unpreionized He/N2/CO2 mixtures is obtained in experiments demonstrating the utility of the technique. Limitations imposed by dielectric parameters are discussed.
Electron-attachment rate constant for Cl2 at room temperature and 250 °C
Authors: Rokni M. , Jacob J. H. , Mangano J. A.
Published: February 2003

The electron-attachment rate constant for Cl2 has been measured in mixtures of N2/Cl2 and Ar/Cl2 at room temperature and at 250 °C in an electron-beam-controlled discharge. From these measurements and the use of a numerical solution of the Boltzmann equation we have been able to calibrate the relative electron-attachment cross section of Cl2 that has been measured by Tam and Wong and by Kurepa and Belic. The peak value of this cross section that gives the best fit to our data is 2.2×10−16 cm2 at room temperature.
Chemical effect in (LVV) Auger spectra of third-period elements (Al, Si, P, and S) dissolved in copper
Authors: Hiraki A. , Kim S. , Kammura W. , Iwami M.
Published: February 2003

Valence electronic states of third-period elements (Al, Si, P, and S) dissolved in Cu were pursued through the chemical effect of the LVV Auger transition from these elements using Auger electron spectroscopy (AES). Indeed, the LVV Auger signals of Al, Si, P, and S in Cu hosts differed completely from those in the pure (metal or semiconductor) states, indicating the presence of the definite chemical effect. The origin of the chemical effect was discussed in connection with similar studies by soft x-ray spectroscopy (SXS).
A new technique for fabricating cryogenic laser-fusion targets using cold-gas jets
Authors: Kim K. , Smoot B. J. , Woerner R. L. , Hendricks C. D.
Published: February 2003

A new technique of fabricating a uniform layer of solid DT inside a glass microshell has been developed using a heater-wire–cold-gas-jets combination. A D2-filled glass microsphere was continuously cooled by two cold-helium-gas jets, and a controlled amount of current was pulsed through a heater wire surrounding the microshell. This gave rise to fast evaporation and refreezing of the D2 inside the glass shell, resulting in a uniform layer of frozen D2. This new scheme has potential application in the development of a target-fabrication system which would allow for continuous fabrication, inspection, and delivery of cryogenic laser-fusion targets.
Selective optical excitation and inversions via the excimer channel: Superradiance at the thallium green line
Authors: Chilukuri Santaram
Published: February 2003

Inversion and superradiance at the Tl green line (5351 Å) has been observed using Tl-Hg and Tl-Cd-Ar systems pumped optically via the excimer channel with a pulsed nitrogen dye laser. Superradiant power outputs up to 200 W averaged over the pulse (without any mirrors) have been obtained with a 90-cm-long Tl-Hg tube. The general applicability of this method to other excimer systems should provide a means of generating coherent radiation at new wavelengths and in understanding collision processes.
Annealing behavior of the oxygen donor in silicon
Authors: Kanamori Akihiro
Published: February 2003

The behavior of the oxygen donor in Czochralski silicon crystals was investigated by resistivity measurement. Annealing at 475 °C was employed to produce an oxygen donor, and the donor concentration was reduced to some extent by heat treatment at 550 °C for 20 h. The results were compared with those reported in the 1950’s and 1960’s. The reduction rate was far smaller than that obtained in the 1950’s, and complete annihilation was not observed, even after 20-h annealing. A model was proposed to interpret the difference in the reduction behavior of the oxygen donor between the old and today’s crystals, in terms of some species which neutralize the donor. A numerical calculation based on this model was made to predict the reduction behavior and was found to be in reasonable agreement with the experimental results.
Effect of cavity length on stripe-geometry DH laser output linearity
Authors: Lynch R. T. , Small M. B. , Hung R. Y.
Published: February 2003

We report here a strong correlation between cavity length and the severity of nonlinearities in light-output–vs–current (P-I) curves observed in oxide-stripe geometry (GaAl)As DH lasers. Cleaving kinky long (∼500 μm) lasers results in two or more shorter (150–250 μm) units, all of which show kinks with reduced severity shifted to higher optical power. When cleaved short enough, the lasers show no kinks up to 25 mW. A similar result is seen when comparing units originally cleaved with long or short cavities. An explanation is offered in terms of the difference in lateral mode stability in long versus short lasers.
The technology of solid-fuel-layer targets for laser-fusion experiments
Authors: Musinski D. L. , Henderson T. M. , Pattinson T. R. , Tarvin J. A.
Published: February 2003

An apparatus which produces uniform solid-fuel layers in glass-shell targets for laser irradiation is described. A low-power cw laser pulse is used to vaporize the fuel within a previously frozen target which is maintained in a cold-helium environment by a cryogenic shroud. The rapid refreezing that follows the pulse forms a uniform fuel layer on the inner surface of the glass shell. This apparatus and technique meet the restrictions imposed by the experimental target chamber. The method does not perturb the target position; nor does it preclude the usual diagnostic experimets since the shroud is retracted before the main laser pulse arrives. Successful laser irradiation and implosion of solid-fuel-layer targets at KMSF have confirmed the effectiveness and reliability of this system and extended the range of laser-target-interaction studies in the cryogenic regime.
An 18O study of the thermal oxidation of silicon in oxygen
Authors: Rosencher E. , Straboni A. , Rigo S. , Amsel G.
Published: February 2003

The mechanism of thermal oxidation of silicon in dry oxygen was studied using 18O as the tracer. SiO2 layers first grown in natural oxygen (1300–3000 Å) were further grown in highly 18O-enriched oxygen for 8.5 h at 930 °C. 18O profiling was carried out using the 629-keV narrow resonance in the nuclear reaction 18O(p,α)  15N. The resulting SiO2 films consist of two 18O-rich layers, 7% near the SiO2 surface and 93% near the Si-SiO2 interface, while the bulk 18O concentration is very low. The results suggest that the oxide grows mainly through long-range migration of oxygen, favoring models based on the transport of molecular oxygen.
High-power coupled-multiple-stripe phase-locked injection laser
Authors: Scifres D. R. , Streifer W. , Burnham R. D.
Published: February 2003

A semiconductor injection device consisting of 10 periodically spaced filaments coupled by curved waveguide sections has been demonstrated. This coupled-multiple-stripe (CMS) laser produces a phase-locked TE polarized beam with a linear powerd–vs–pumping-current characteristic up to 0.9 W/facet and a beam divergence of less than ≈4° along the p-n junction plane in pulsed operation at room temperature. The threshold is 400 mA and differential quantum efficiencies of 65% are observed.
Spectral hole burning in GaAs junction lasers
Authors: Patel Navin B. , Brosson P. , Ripper J. E.
Published: February 2003

Spectral hole burning corresponding to a gain reduction of the order of 1% has been observed in GaAs junction lasers. This observation is made possible by the use of the strong superradiant amplification of the spontaneous emission along the junction.
Abrupt Ga1−xAlxAs-GaAs quantum-well heterostructures grown by metalorganic chemical vapor deposition
Authors: Dupuis R. D. , Dapkus P. D. , Garner C. M. , Su C. Y. , Spicer W. E.
Published: February 2003

Multiple-quantum-well Ga1−xAlxAs-GaAs heterostructures grown by metalorganic chemical vapor deposition have been analyzed by Auger electron spectroscopy combined with simultaneous argon-ion sputter etching. The chemical-interface widths of the Ga0.45Al0.55As-GaAs heterojunctions are determined to be ≲17 Å. In addition, no Al is detected in the GaAs quantum wells.
Freedericksz transition and anchoring effects in the oblique configuration of a nematic liquid crystal
Authors: Motooka T. , Fukuhara A. , Suzuki K.
Published: February 2003

The following is theoretically shown: (1) The Freedericksz transition for nematic liquid crystals (NLC) can be defined in a clear-cut way for cases where NLC is initially aligned uniformly in an arbitrary direction α0 and is weakly anchored to cell walls; (2) the critical magnetic field for the transition varies according to the anchoring stiffness. These transition phenomena will make it possible to estimate the anchoring stiffness at the wall.
Transient response of hybrid bistable optical devices
Authors: Garmire E. , Marburger J. H. , Allen S. D. , Winful H. G.
Published: February 2003

The response of a hybrid bistable optical device to step inputs of light was studied experimentally. The results confirm theoretical predictions concerning the dependence of switching time on the applied light increment. For the first time the phenomenon of ’’critical slowing down’’ is observed directly.
Optical switching and bistability in tunable lasers
Authors: Levin K. H. , Tang C. L.
Published: February 2003

We report the observation of optical switching and bistability, and such related effects as hysteresis, optical memory, multistability, and differential gain, in an electro-optically tuned cw dye laser. Similar effects should be observable in other tunable lasers.
The dependence of an acoustically nonresonant optoacoustic signal on pressure and buffer gases
Authors: Wake Douglas R. , Amer Nabil M.
Published: February 2003

The dependence of an acoustically nonresonant signal on the buffer gas, pressure, and microphone response is presented. We extend the theoretical treatment of Kerr and Atwood to account for the strength of the observed signal. Considerations for detector optimization are discussed.
Detection of small molecules by magnetically tuned frequency-modulated atomic line sources
Authors: Koizumi Hideaki , Hadeishi Tetsuo , McLaughlin Ralph D.
Published: February 2003

Small molecules such as NO, OH, I2, S2, SO2, NO2, and HCHO display discrete sharp electronic rotational-vibrational lines. Utilizing the Zeeman effect, one component of an atomic emission line can be made to exactly coincide with a sharp molecular line while the other component is shifted so that there is no overlap with this line. When large molecules undergo electronic transitions it is not possible to resolve the rotational structure in the vast majority of cases. Therefore, the difference in absorption between the σ± components is proportional to the density of the molecules showing sharp absorption but is not influenced by other molecules. These phenomena can be used to achieve highly sensitive and selective detection of small molecules.
Compact sealed photopreionized TEA CO2 laser without heterogeneous catalysis or gas recycling
Authors: Norris B. , Smith A. L. S.
Published: February 2003

A compact photopreionized CO2 TEA laser is reported which operates on a single sealed gas mixture for ≳106 pulses without the necessity for heterogeneous catalysis, gas recirculation, or careful control of the gas mixture. Discharge arcing is prevented by (i) suppression of the CO2 dissociation and O2 formation with the addition of CO to the basic CO2-N2-He mixture and (ii) limitation of the attachment of the preionization electrons by the use of a short (∼60 ns) delay between the preionizing and main discharges with integral delay electronics.
Emission cross section and flashlamp-excited NdP5O14 laser at 1.32 μm
Authors: Choy M. M. , Zwicker W. K. , Chinn S. R.
Published: February 2003

The 4F3/2→4I13/2 emission cross section of NdP5O14 at 1.32 μm has been determined from both spontaneous and stimulated emission measurements. The relative performance of a flashlamp-excited NdP5O14 laser at 1.32 and at 1.05 μm has also been evaluated. At 1.32 μm a multimode output energy of 2.7 mJ has been achieved with 1.6 J input.
Arc oscillations in a horizontal rare-earth metal iodide/cesium iodide/mercury arc induced by an external magnetic field
Authors: van den Hoek W. J. , Visser J. A.
Published: February 2003

A novel type of periodic motion has been observed in a horizontal 50-Hz ac DyI3/CsI/Hg arc, placed in a magnetic field perpendicular to the arc axis. The arc oscillates in the vertical plane with frequencies of 0.5–5 Hz. A mechanism involving a time-varying arc constriction due to periodic metal iodide evaporation and condensation is discussed in terms of the balance between Lorentz force and buoyant forces.
Growth and properties of graded band-gap AlxGa1−xAs layers
Authors: Kordos P. , Powell R. A. , Spicer W. E. , Pearson G. L. , Panish M. B.
Published: February 2003

Graded band-gap AlxGa1−xAs layers were grown using isothermal LPE techniques together with undersaturated solutions. The layer thicknesses were 1500–2500 Å and the value of x in the graded layers increased monotonically to ≈0.8 at the surface. The Al depth profiles, as measured by Auger analyses, are in good agreement with those derived by assuming rapid Al diffusion through the liquid boundary layer resulting from partial dissolution of the substrate surface. It was found that the graded-layer thickness could be controlled by varying the degree of undersaturation of the solution at any given temperature.
Dual-wavelength demultiplexing InGaAsP photodiode
Authors: Campbell J. C. , Lee T. P. , Dentai A. G. , Burrus C. A.
Published: February 2003

We report the successful operation of a new photodiode structure capable of detecting and demultiplexing two wavelength bands simultaneously. Wavelength discrimination is achieved with a multilayer structure that incorporates p-n junctions in two InxGa1−xAsyP1−y layers having different band gaps. In initial devices ’’crosstalk’’ between the photoresponses is less than −10 dB at each response peak.
Gettering effect by oxygen implantation in SOS
Authors: Yamamoto Y. , Wilson I. H. , Itoh T.
Published: February 2003

Rutherford backscattering and Hall measurements for oxygen- and/or boron-implanted SOS samples have revealed that the oxygen implantation into the sapphire substrate through the silicon layer improves the crystalline quality in the surface region after annealing and is effective in suppressing the anomalous increase of the carrier concentration due to the aluminum diffusion from the substrate during annealing.
Junction characteristics of Al-Al2O3-CdS diodes fabricated by molecular beam epitaxy
Authors: Tsang W.M. , Cameron D. C. , Duncan W.
Published: February 2003

The I-C and C-V characteristics of Al-Al2O3-CdS diodes have been investigated, the diodes being fabricated by growing CdS films by MBE on epitaxial aluminum. The forward-bias current is proportional to exp(qv)/nkt, and under certain growth conditions n values of 2.2 have been obtained. The epitaxial CdS films exhibit a thermo-emf appropriate to p-type CdS, which is considered to be due to an inversion layer within the CdS and adjacent to the Al2O3-CdS interface. The polarity of the bias voltage for forward-bias conduction suggests that a p-n junction may exist within the CdS film.
Calorimetric measurement of LiNbO3 waveguide absorption losses
Authors: Allen S. D. , Garmire E. , Bass M. , Packer B.
Published: February 2003

This paper reports the first measurement of optical-absorption loss in LiNbO3 waveguides and bulk material. This is also the first demonstration of calorimetry as a feasible technique for measuring waveguide absorption in integrated optics. Results indicate that in LiNbO3 out-diffused waveguides the absorption is two orders of magnitude lower than the total loss, implying that the predominant loss mechanism is scattering. The ultimate sensitivity limit for calorimetric determination of absorption losses appears to be ∼10−4 dB/cm for optimized geometries.
Secondary-ion mass spectrometry (SIMS) analysis of electron-bombarded soda-lime-silica glass
Authors: Gossink R. G. , Lommen T. P. A.
Published: February 2003

Al-coated glasses of molar composition 20Na2O-10CaO-70SiO2 have been bombarded with a rastered beam of either 7- or 10-keV electrons. SIMS analysis of these glasses indicates a near-surface layer deficient in Na, bounded by a steep rise of the Na signal. The thickness of this layer increases with electron-bombardment time until it becomes close to the expected maximum range of electron penetration. No Ca displacement was observed. Below the Na-deficient layer, a layer containing uncombined Na was found.
Phase conjugation at 10.6 μm by resonantly enhanced degenerate four-wave mixing
Authors: Lind R. C. , Steel D. G. , Klein M. B. , Abrams R. L. , Giuliano C. R. , Jain R. K.
Published: February 2003

A resonantly enhanced phase-conjugate 10.6-μm signal has been generated in the saturable absorber SF6. Direct evidence of aberration correction is shown through the use of far-field photographs taken with a pyroelectric vidicon camera. Reflection coefficients of 7% have been achieved in a few Torr of SF6 for a 2-cm interaction length.
Scalar-wave approach for single-mode inhomogeneous fiber problems
Authors: Yeh C. , Casperson L. , Brown W. P.
Published: February 2003

It has generally been accepted that accurate results may be obtained using the scalar-wave approach to solve problems dealing with inhomogeneous multimode guided-wave structures. The problem of the applicability of the scalar-wave approach to obtain wave propagation characteristics in single-mode fiber or integrated optical circuit guides with inhomogeneous index profiles is examined in this paper. It is shown that if certain limiting conditions are satisfied, the scalar-wave approach will yield valid results for single-mode structures. These limiting conditions are usually satisfied by many practical single-mode inhomogeneous fibers or IOC structures.
Low-current-threshold and high-lasing uniformity GaAs–AlxGa1−xAs double-heterostructure lasers grown by molecular beam epitaxy
Authors: Tsang W. T.
Published: February 2003

GaAs–AlxGa1−xAs double-heterostructure (DH) lasers that have current-threshold densities at least as low as similar-geometry DH lasers prepared by liquid-phase epitaxy have been prepared by molecular beam epitaxy for the first time. These broad-area lasers exhibited excellent stability and uniformity in lasing-filament distribution across the entire junction plane and throughout the entire current injection range up to catastrophic damage. The burn-off powers were typically about 14 W/mm. The differential quantum efficiencies were about 40%.
X-ray preionization for electric discharge lasers
Authors: Lin Shao-Chi , Levatter Jeffrey I.
Published: February 2003

Using x rays of 60–200-keV photon energy (λ∼0.06–0.2 Å) as an ionizing radiation source in a transmission-line-driven low-inductance discharge chamber, we have succeeded in generating spatially homogeneous pulsed avalanche discharges of several liter volume at greater than 1 atm pressure for up to 100-nsec duration. In concurrent laser generation experiments with relatively lossy windows, we have observed high-optical-quality pulsed uv laser output of up to 2 J/liter from such discharges in rare-gas/halogen mixtures, and ir laser output of up to 12.5 J/liter from a He/N2/CO2 mixture.
Ellipsometric study of silicon implanted with boron ions in low doses
Authors: Watanabe K. , Miyao M. , Takemoto I. , Hashimoto N.
Published: February 2003

Ellipsometry was applied to estimate crystal damage in silicon caused by boron-ion implantation in low doses. A highly sensitive parameter for crystal damage is proposed which is derived from the extinction coefficient of the complex refractive index. Crystal damage caused by ion implantation at doses as low as 3×1011 cm−2 and the annealing effect on crystal damage of heat treatment in dry N2 ambient after ion implantation were clearly detected by the parameter.
Plasma anodization of oxygen-sputtered GaAs surfaces
Authors: Shinoda Yukinobu , Yamaguchi Masao
Published: February 2003

A simple method of preparing plasma-grown anodic oxide on GaAs with improved physical and electrical properties is described. A GaAs surface was sputtered by positive oxygen ions prior to the plasma anodization, resulting in a Ga-rich oxide layer on the surface. The oxide formed through this Ga-rich layer had a low pin hole density and exhibited high breakdown voltages (3×106 V/cm) and less hysteresis in MOS-device C-V characteristics.
An experimental determination of the effective masses for GaxIn1−xAsyP1−y alloys grown on InP
Authors: Nicholas R. J. , Portal J. C. , Houlbert C. , Perrier P. , Pearsall T. P.
Published: February 2003

The band-edge effective mass for conduction electrons in GaxIn1−xAsyP1−y has been determined for several different alloy compositions covering the complete range of alloys grown lattice-matched on InP. Measurements show that the effective mass varies nearly linearly with alloy composition.
The effect of dc current bias on sustained oscillations in (Al,Ga)As double-heterostructure lasers
Authors: Dixon R. W. , Beurrier H. R.
Published: February 2003

Sustained oscillations in proton-bombardment-delineated stripe-geometry (Al,Ga)As double-heterostructure injection lasers are shown to be adversely influenced (enhanced) by the presence of dc current bias in the devices. The time constant for this enhancement is found to be in the range 2–5 μsec and is interpreted as being thermal in origin. A previously proposed saturable absorber model of pulsations is qualitatively consistent with these results.
Sulfur 1S0-1D2 laser by OCS photodissociation
Authors: Powell H. T. , Prosnitz D. , Schleicher B. R.
Published: February 2003

Strong laser oscillation has been obtained on the electric-dipole-forbidden 1S0-1D2 transition of atomic sulfur using 146-nm photodissociation of OCS. A photolytic mixture of OCS with N2 and SF6 produced optimum laser performance. Based on the laser output energy of 5 mJ at 772.5 nm, we infer that an energy density of 2.5 J/liter was stored in the laser transition immediately following photolysis. The one-half quenching time of S(1S) atoms was approximately 1 μs for these conditions.
Observation of dislocations in cadmium telluride by cathodoluminescence microscopy
Authors: Nakagawa K. , Maeda K. , Takeuchi S.
Published: February 2003

A one-to-one correspondence between deformation-produced dark spots in cathodoluminescence (CL) micrographs and dislocations has been demonstrated in n-type CdTe by comparing the CL pattern with the etch-pit pattern developed with a new etchant which has been ascertained to reveal dislocations by a successive polishing and etching method.
Oxygen partial pressure dependence of the fixed surface-state charge QSS due to thermal oxidation of n- (100) silicon
Authors: Murarka S. P.
Published: February 2003

The fixed surface-state charge QSS has been determined for (100) n-type silicon oxidized in different partial pressures of oxygen (pO2). It has been found that the QSS is directly proportional to pO2 and is given by QSS×10−10= (14.1±12.7) pO2+(5.44±0.78) in the pO2 range 0.1–1.0 where pO2 is the partial pressure of oxygen in the oxygen-nitrogen mixture. The results are discussed in view of the concentration of the excess silicon present in silicon near the oxide-silicon interface and its assumed relationship to the length of oxidation-induced stacking faults in silicon.
Theoretical cross sections for ionization of metastable excimers Ne*2 and Ar*2 by electron impact
Authors: McCann K. J. , Flannery M. R. , Hazi A.
Published: February 2003

Cross sections for the ionization of the metastable excimers Ne*2(1,3Σ+u) and Ar*2(1,3Σ+u) by electron impact are calculated in the binary-encounter approximation for collision energies E (eV) in the range 5⩽E⩽50 eV. They have maximum values ∼10−15 cm2 and are within 50% higher than the cross sections for ionization of the corresponding metastable atomic states.
A highly stable long-life GaP-GaAlP heterojunction cold cathode
Authors: Kan Hirofumi , Nakamura Tsutomu , Katsuno Hironobu , Hagino Minoru , Sukegawa Tokuzo
Published: February 2003

By a new activation method, namely, activation by Cs, Sb, and O2, stabilized cold cathodes could be obtained, and continuous operation over 3000 h has been achieved with a GaP-GaAlP cold cathode. It is found that a major source of rapid efficiency loss of the cold cathode is the loss of Cs and/or O2 from the cold-cathode surface.
Junction formation with pure and doped polyacetylene
Authors: Ozaki M. , Peebles D. L. , Weinberger B. R. , Chiang C. K. , Gau S. C. , Heeger A. J. , MacDiarmid A. G.
Published: February 2003

A variety of rectifying junctions have been fabricated using doped and undoped (CH)x. Schottky diodes formed between metallic AsF5-doped (CH)x and n-type semiconductors indicate high [CH(AsF5)y]x electronegativity. The p-type character of undoped trans- (CH)x is confirmed by Schottky-barrier formation with low-work-function metals. An undoped p- (CH)x : n-ZnS heterojunction has been demonstrated with an open-circuit voltage of 0.8 V. These results point to the potential of (CH)x as a photosensitive material for use in solar-cell applications.
Low-noise parametric amplification at 35 GHz in a single Josephson tunnel junction
Authors: Mygind J. , Pedersen N. F. , Soerensen O. H. , Dueholm B. , Levinsen M. T.
Published: February 2003

Parametric amplification at 35 GHz has been obtained using a single Josephson tunnel junction as the active element. The amplifier was operated in the singly quasidegenerate mode with a pump frequency at 70 GHz. The noise temperature was measured and found correlated with the gain. At the highest gain achieved, 11.6 dB, the noise temperature was 400 K. The noise temperature was reduced considerably by decreasing the gain. At 8 and 4 dB we found 165±25 K and 50±30 K, respectively.
A new electron-beam pumped XeF laser at 486 nm
Authors: Ernst W. E. , Tittel F. K.
Published: February 2003

Laser emission has been observed from XeF on the C (3/2) →A (3/2) transition at 486 nm with a spectral bandwidth of 12 nm. A peak laser power of 5 kW was obtained from Ar/Xe/NF3 mixtures in the ratio of 600 : 2 : 1 at total pressures of 350–800 kPa excited by 1-MeV 20-kA electron-beam pulses of 8-ns duration. Lasing can also occur on the usual B (1/2) →X (1/2) transition at 353 nm with an appropriate set of cavity reflectors under the same operating conditions.