bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of amplified phase-conjugate reflection and optical parametric oscillation by degenerate four-wave mixing in a transparent medium
Authors: Pepper David M. , Fekete Dan , Yariv Amnon
Published: February 2003

We report on the observation of amplified reflection and optical parametric oscillation via degenerate four-wave mixing in a nonresonant medium. The process is mediated through the third-order nonlinear susceptibility in a transparent liquid medium, CS2. A collinear mixing geometry is utilized to obtain long interaction lengths and polarization discrimination is used to separate the pump and signal fields.
Cryosorption-pumped cw chemical laser
Authors: Newton K. R. , Bernstein R. B.
Published: February 2003

A miniature cw chemical laser is described which can serve as a convenient multiline source in the ir. It employs condensible carrier gases with cryosorption pumping only (thus no moving parts) to deliver 300 and 200 mW, respectively, of HF and HCl radiation. Five laser reactions with a total of nine lines each of HCl and HF in the regions 2.6–3.0 and 3.6–4.0 μm, respectively, have been observed. For the F+CH4 reaction (using SF6 as the F atom source and carrier gas) most of the power extracted is in the P1(4) line. For the Cl+HBr reaction, the full laser power is emitted in the P1(5) line.
Chlorine isotope enrichment by the photochemical reaction of chlorine molecules using the Ar ion laser
Authors: Suzuki Kazuo , Kim Pil Hyon , Namba Susumu
Published: February 2003

For isotope enrichment of chlorine, Cl2 was excited by a 488-nm line of the Ar ion laser and reacted with tetrachloroethylene. It was found that the reaction rate was limited to the excitation rate of Cl2 by the laser. The enrichment factor of 37Cl in residual Cl2 increased linearly with the irradiation time and the result agreed with the approximate relation derived from the reaction rate. The enrichment factor of 1.17 was obtained after 120 min irradiation at the laser power of 180 mW.
Intense laser emission from electron-beam-pumped ternary mixtures of Ar, N2, and POPOP vapor
Authors: Marowsky G. , Cordray R. , Tittel F. K , Wilson W. L. , Collins C. B.
Published: February 2003

Powerful laser output was observed at 381 nm from electron-beam-pumped ternary mixtures of argon-nitrogen and 2,2′-p-phenylinebis(5-phenyloxazole) (POPOP) dye vapor. The injection of the subthreshold 380.5-nm N2 line into the electrically excited gain profile of POPOP vapor has been identified as a pumping mechanism.
Laser plasma isolator for a retropulse in a CO2 laser amplifier chain
Authors: Kawamura Y. , Takeda H. , Matoba M. , Nakai S. , Yamanaka C.
Published: February 2003

A laser plasma isolator was developed to attenuate a retropulse in a high-power CO2 laser system. An attenuation ratio of 1/20 of a main laser beam (∼1-J 3-nsec pulse-width FWHM) was obtained by blowing off a carbon plasma induced by a plasma production laser beam (∼0.5-J 3-nsec pulse-width FWHM) onto the waist of the main laser beam.
Invariant properties of helical-circular metallic waveguides
Authors: Marhic M. E. , Kwan L. I. , Epstein M.
Published: February 2003

Experimental evidence shows that toroidal or helical-circular metallic waveguides, operating on the whispering-gallery principle, can be bent significantly without affecting either their ray-guiding or modal properties. These remarkable properties, reported here for the first time for any type of surface guide, result from the fact that the allowed deformations are geodesic and conserve the curvature of the rays. Scanning in one or two dimensions with a diffraction-limited beam has been achieved.
Electron-beam-pumped KrF laser with a neon-argon diluent
Authors: Oomen G. L. , Witteman W. J.
Published: February 2003

Enhanced laser action of KrF* is observed for a diluent mixture of Ar and Ne. If the Ar diluent is replaced by neon, the maximum output is practically unchanged. For an optimized mixture of Ne and Ar the output is increased by more than 50%. The system, with an active length of 50 cm and a diameter of 4 cm, is transversely excited by an e-beam with a pulse duration of 30 nsec, current density of 100 A/cm2, and energy of 750 kV. The maximum output energy is 2.1 J.
Correspondence between the antimony contents of the sputtered films and the targets
Authors: Sabnis Anant G. , Moldovan Anton G.
Published: February 2003

Thin films of antimony-doped tin dioxide are deposited by dc sputtering from sintered targets containing 10, 20, and 30% Sb2O3 by weight of SnO2. The concentrations of Sb, Sn, and O in the films and in the target surfaces are determined by using Auger electron spectroscopy. It is observed that the Sb content in the films depends nonlinearly upon the Sb2O3 contents of the targets, and that the films become increasingly resistive with Sb2O3 content beyond 10% in the target. In the films the Sb content is less than the Sn content, although the reverse is true in the case of the targets.
Study of two-dimensional Gunn domain dynamics using a stroboscopic SEM
Authors: Masuda M. , Ogura T. , Koyama J.
Published: February 2003

Two-dimensional domain dynamics has been clarified in a cathode-slanted planar Gunn diode under the pulse-biased operation using a stroboscopic scanning electron microscope. Experimental results are in reasonable agreement with theoretical results.
Influence of film stress and thermal oxidation on the generation of dislocations in silicon
Authors: Bohg A. , Gaind A. K.
Published: February 2003

The experimental data presented here show that the generation of dislocations in Si along Si3N4 edges is due to the cumulative effect of the Si3N4 stress field near the nitride edge and to the point defects produced during thermal oxidation. Within our experimental range, the stress along the Si3N4 edges alone is not sufficient to generate dislocations in silicon. We have determined a critical ratio of Si3N4 thickness to SiO2 thickness which does not lead to the generation of dislocations.
Monte Carlo simulation of electron penetration through thin films of PMMA
Authors: Adesida I. , Shimizu R. , Everhart T. E.
Published: February 2003

The electron penetration through thin films of PMMA has been simulated using two different Monte Carlo approaches. One approach is conventional, in that the energy loss of the electron along its trajectory is computed using the continuous-slowing-down approximation. The statistical nature of inelastic scattering events, as well as the elastic scattering events, is taken into account in the second approach, which is based on an extension of Gryzinski’s semiempirical expression for the excitation of core electrons and also the excitation of valence electrons through the use of an appropriate mean binding energy. The energy distribution of transmitted electrons through PMMA films of various thicknesses obtained by both methods are compared. The second approach is shown to give a more realistic answer for the transmitted electron energy distribution.
LEIT effect in metal-insulator-semiconductor tunnel junctions
Authors: McCarthy S. L. , Lambe John
Published: February 2003

Light emission via inelastic tunneling (LEIT) has been observed from the metal-insulator-semiconductor tunnel-junction Al-Al2O3- Sn-doped indium oxide (ITO). The spectra exhibit the bias-voltage-dependent upper-frequency quantum cutoff relation. These devices were stable at room temperature for months at a time while biased to 3 V. The external quantum efficiency of this metal-insulator-semiconductor system is about 0.1 that of the metal-insulator-metal system Al-Al2O3-Ag. Enhancement of the light emission using silver particle resonators is also reported.
Plastic deformation of V3Si single crystals at elevated temperatures
Authors: Mahajan S. , Wernick J. H. , Chin G. Y. , Nakahara S. , Geballe T. H.
Published: February 2003

Plastic stress-strain characteristics of V3Si single crystals, oriented for [110] compression, have been ascertained under dynamic conditions between 1200 and 1800 °C. This is believed to be the first such report on the A-15 compound superconductors. In the range 1200–1500 °C, yield strength is very temperature sensitive, whereas the sensitivty is not very pronounced between 1600 and 1800 °C. In addition, substructures introduced by a ∼7% compressive strain at different temperatures appear to have no deleterious effects on transition temperatures and transition widths.
Core-level photoemission of the Cs-O adlayer of NEA GaAs cathodes
Authors: Spicer W. E. , Lindau I. , Su C. Y. , Chye P. W. , Pianetta P.
Published: February 2003

Negative-electron-affinity (NEA) photocathodes are made possible by adding Cs and oxygen to the surface of Si or GaAs and other III-V materials. In this work, the chemistry of the Cs-O adlayer on GaAs is studied by following the Cs, Ga, and As core-level shifts at hν=120 eV. The changes in binding energy for the Cs core levels were studied as a function of oxygen exposure. Oxygen was found to bind to As of GaAs for exposures above 10 L. These results are discussed in terms of the importance of Cs suboxides, in relation to the interfacial barriers which limit the ultimate photothreshold of NEA cathodes.
Diffused homojunction lead-sulfide-selenide diodes with 140 K laser operation
Authors: Lo Wayne , Swets Don E.
Published: February 2003

We have fabricated PbS1−xSex homojunction diode lasers which operate up to 90 K cw and 140 K pulsed. Photon confinement was achieved by a carrier-concentration profile rather than the usual compositional heterojunction. This results in a tuning range of 350 cm−1 under cw operation.
Sagnac fiber-ring interferometer gyro with electronic phase sensing using a (GaAl)As laser
Authors: Thompson D. E. , Anderson D. B. , Yao S. K. , Youmans B. R.
Published: February 2003

Rotation-sensitive fiber-ring interferometers have been demonstrated using balanced heterodyne phase-detection techniques. Red He/Ne and infrared (GaAl)As lasers were employed with balanced elasto-optic frequency shifters as sources. Rotation-induced phase shift (Sagnac effect) was demonstrated using both single-mode and multimode low-loss fibers.
The energy level of thallium in silicon
Authors: Brotherton S. D. , Gill A.
Published: February 2003

Thermal-emission-rate measurements, including DLTS, have been made on thallium-doped gated diode structures fabricated using an implanted thallium source. The rate of thermal emission was found to be strongly field dependent, giving results comparable to the prediction of the simple Poole-Frenkel model. The field-free trap separation from the valence-band edge was determined to be 0.24 eV, with a hole-capture cross section of 2.4×10−14 cm2.
Deep-level traps and the conduction-band structure of InP
Authors: Majerfeld A. , Wada O. , Choudhury A. N. M. M.
Published: February 2003

Three traps found in n-type InP with emission activation energies ΔEe=0.43, 0.59, and 0.63 eV are analyzed. The position of the energy levels for these traps, relative to the lowest conduction-band minimum Γ, are ET=0.34, 0.20, and 0.24 eV, respectively. It is shown that the 0.43-eV trap emits to and captures electrons from the Γ minimum and exhibits a thermally activated capture cross section with a barrier energy of 0.09 eV. Very good agreement is found between the capture cross sections derived from capture and from emission experiments: σ∞=3.4×10−15 and 5.8×10−15 cm2, respectively. It is concluded from detailed emission and capture studies that the 0.59- and 0.63-eV traps emit and capture carriers via the higher-lying L minima. A value of 0.39 eV for the intervalley L-Γ energy separation is consistent with the observed emission and capture properties of both centers.
Separation of storage effects in monolithic p
n diode correlators
Authors: Lo F. C. , Gunshor R. L. , Pierret R. F. , Elliott J. K.
Published: February 2003

The use of a combination of steady and pulsed dc biasing of a ZnO monolithic SAW device enabled a distinction to be made between surface-state and pn diode storage mechanisms in a single memory correlator device. By use of demonstrated biasing schemes, storage times of from tens of microseconds to tens of miliseconds are available in a single device.
Negative and positive cesium ion studies
Authors: Kuehn D. G. , Sutliff D. E. , Chanin L. M.
Published: February 2003

Mass spectrometric analyses have been performed on the positive and negative species from discharges in Cs, He-Cs, and He-H2-Cs mixtures. Sampling was conducted through the electrodes of normal glow discharges and from close-spaced heated-cathode conditions, which approximate a cesium thermionic converter. No negative Cs ions were observed for Cs pressures less than 10−2 Torr. Identified species included Cs+, Cs+2, Cs−, and what appeared to be multiply charged ions. Low-mass negative and positive ions attributed to H2 were observed when an He-H2 mixture was also present in the discharge region.
A model for the large-amplitude hysteresis in MIS structures on InSb
Authors: Buxo J. , Esteve D. , Farre J. , Sarrabayrouse G. , Simonne J.
Published: February 2003

Time-instability measurements of the capacitance-voltage (C-V) characteristics of InSb MIS devices show that the flatband voltage shift follows VG=K (V)  log(1+t/τ) and appears to be caused by tunneling of free carriers from the semiconductor surface into insulator traps. The analysis of such a mechanism emphasizes the influence of the semiconductor band-gap width on the values of K for InSb substrates at 77 °K leading to about a 100 times larger instability than silicon sustrates at 300 °K for an equal value of the insulator trap density.
Transition radiation from neutral beams of hydrogen isotopes
Authors: DeRaad L. L. , Erber T.
Published: February 2003

Transition radiation can be emitted by neutral-charge structures, such as atoms, crossing the interface between dielectric media. Intensities in excess of 103 photons/sec, in the energy range 1–50 keV, may be obtained from high-power (≳100 kV, ≳1 A) beams of neutral hydrogen isotopes incident on foils. This effect may have practical implications for constructing energy-sensitive monitors for intense neutral beams.
X-ray-preionized high-pressure KrF laser
Authors: Sumida Shin , Obara Minoru , Fujioka Tomoo
Published: February 2003

As a novel alternative to existing means of preionization, we have used x radiation to preionize a high-pressure KrF laser mixture and found that the x-ray preionization produces a uniform glow discharge for high-pressure KrF laser gas.
Effect of H2 on residual impurities in GaAs MBE layers
Authors: Calawa A. R.
Published: February 2003

The introduction of hydrogen during the MBE growth of GaAs is shown to produce a major improvement in the electrical properties of the epitaxial layers. The observed increase in 77 K electron mobilities reflects a significant decrease in total ionized impurity concentration. Evidence is presented that the dominant residual impurities in MBE-grown GaAs are oxygen and carbon.
Tunable optical gain in the near uv using F+ centers in CaO
Authors: Duran J. , Evesque P. , Billardon M.
Published: February 2003

A tunable amplification around 3600 Å has been demonstrated at low temperatures in the low-energy side of the emission band of CaO crystals doped with F+ centers. The pumping power was delivered by a pulsed nitrogen laser and the optical gain was measured in a coaxial configuration. The observed amplification fits the equations of the pumping cycle for this system reasonably well. The possibility of designing a tunable laser using this material is discussed in light of our experiments.
Effect of grain boundaries in silicon on minority-carrier diffusion length and solar-cell efficiency
Authors: Daud T. , Koliwad K. M. , Allen F. G.
Published: February 2003

The spatial variation of minority-carrier diffusion length in the vicinity of a grain boundary for a polycrystalline silicon sheet has been measured by the use of the EBIC technique. The effect of such a variation on solar-cell output has then been computed as a function of grain size. Calculations show that the cell output drops considerably for grain size smaller than three times the bulk diffusion length.
A refractory lift-off process with applications to high-T
c superconducting circuits
Authors: Howard R. E.
Published: February 2003

A refractory stencil lift-off process utilizing Nb/Cu bilayers is described that is suitable for materials, such as the high-transition-temperature superconductors, which must be deposited on hot (up to 1000 °C) substrates.
Runaway-electron model for x-ray emission in pinched discharges
Authors: Benford Gregory
Published: February 2003

We consider a simple model in which a small fraction of runaway electrons produce the often-observed x-ray emission in pinches. We show the turbulent collision frequency scales as v−3, from fairly general arguments. Simple scalings result, linking the number of runaways with their energy. Fitting to a recent experiment gives a pinch field exceeding the applied field by ∼400. Future experiments can check the scaling without knowing the pinch electric field.
Absolute photon yields in the sputter-induced optical emission process
Authors: Tsong I. S. T. , Yusuf N. A.
Published: February 2003

The absolute photon yield expressed as the number of photons emitted at a particular wavelength per sputtered atom has been measured for 34 elements in NBS standard glass targets bombarded by 20-keV Ar+ ions. The yield values lie in the range 10−2–10−6. The detection limits for these elements in parts per million by weight have also been estimated for given bombardment conditions.
Performance of an Al0.92Ga0.08As/Al0.14Ga0.86As solar cell in concentrated sunlight
Authors: Moon R. L. , James L. W. , VanderPlas H. A. , Nelson N. J.
Published: February 2003

An Al0.14Ga0.86As solar cell with an Al0.92Ga0.08As window has been operated in AM2 sunlight at flux concentrations up to 899 suns with a conversion efficiency at this maximum concentration of 15.5%. Evaluation of the cells shows minority-carrier diffusion lengths ≳2 μm and quantum efficiencies ≈0.85. The use of such a cell for spectral-splitting high-efficiency solar cell applications is discussed.
Epitaxial growth of deposited amorphous layer by laser annealing
Authors: Lau S. S. , Tseng W. F. , Nicolet M-A. , Mayer J. W. , Eckardt R. C. , Wagner R. J.
Published: February 2003

We demonstrate that a single short pulse of laser irradiation of appropriate energy is capable of recrystallizing in open air an amorphous Si layer deposited on a (100) single-crystal substrate into an epitaxial layer. The laser pulse annealing technique is shown to overcome the interfacial oxide obstacle which usually leads to polycrystalline formation in normal thermal annealing.
Arsenic diffusion in silicon melted by high-power nanosecond laser pulsing
Authors: Baeri P. , Campisano S. U. , Foti G. , Rimini E.
Published: February 2003

The time evolution of temperature and melting in amorphous silicon layers laser irradiated was calculated numerically. Experiments were performed in Si crystals implanted with 400-keV As to a dose of 5×1015/cm2 and illuminated with 50-ns-duration Q-switched ruby laser pulse in the energy range 1.0–3.0 J/cm2. Comparison between experimental and calculated results allows a quantitative understanding of the amorphous–to–single-crystal transition. A good agreement was found between the experimental As profiles after laser irradiation and those calculated with a diffusion coefficient of 10−4 cm2/s for As in liquid silicon.
Efficient amplification of a discharge-pumped KrF laser
Authors: Watanabe Shuntaro , Shiratori Susumu , Sato Takuzo , Kashiwagi Hiroshi
Published: February 2003

The output energy of 0.75 J has been obtained with a pulse width of 40 ns and an efficiency of 0.8% by using a uv-preionized KrF amplification system. The stored energy in an amplifier has been improved by a factor of about 1.6 by control of self-breakdown voltage with a change of electrode separation. The measured saturation energy for this device was 51 mJ/cm2 corresponding to a KrF saturation intensity of 1.2 MW/cm2. The small-signal gain coefficient reached 4.3%/cm at a charging voltage of 35 kV.
Intense proton-beam-pumped Ar-N2 laser
Authors: Golden J. , Eden J. G. , Mahaffey R. A. , Pasour J. A. , Ali A. W. , Kapetanakos C. A.
Published: February 2003

Gas laser action using a current and space-charge-neutralized proton beam as a pump source has been demonstrated. Stimulated emission at 357.7 and 380.5 nm, corresponding to the v′=0→v″=1 and v′=0→v″=2 transitions of the N2 (C→B) band, has been observed in Ar/5%N2 gas mixtures. In comparison with electron beams, protons appear to be more efficient for excitation sources of high-pressure uv and visible lasers.
A kinetics scheme for the XeF laser
Authors: Finn T. G. , Palumbo L. J. , Champagne L. F.
Published: February 2003

A kinetics scheme is described for electron-beam excitation of the XeF laser in a neon diluent. Both Ne+ and Ne* channels contribute significantly to the formation of the upper laser level. In each chain an important Penning ionization process leads to the formation of Xe+, which is the major intermediary in forming the upper laser level. Xe+2 is found to be the dominant absorber of laser radiation. The effect of the weakly bound XeF ground state is discussed.
Discharge pumped mercuric halide dissociation lasers
Authors: Burnham R.
Published: February 2003

Lasers on the (B-X) transitions in HgCl, HgBr, and HgI at 558, 502, and 443 nm, respectively, have been excited in a uv-preionized transverse electric discharge. Marked increases in laser efficiency and output power were obtained when nitrogen was added to the laser discharge.
Photodissociation lasers using forbidden transitions of selenium atoms
Authors: Powell H. T. , Ewing J. J.
Published: February 2003

Weak laser oscillation has been demonstrated on the 489- and 777-nm electric-dipole-forbidden 1S0–3P1 and 1S0–1D2 transitions of the selenium atom. Carbonyl selenide has been photolyzed at 172 nm by Xe*2 radiation to produce the Se(1S0) excited state.
Emitter current suppression in a high-low-junction emitter solar cell using an oxide-charge-induced electron accumulation layer
Authors: Neugroschel A. , Lindholm F. A. , Pao S. C. , Fossum J. G.
Published: February 2003

A new type of high-low-junction emitter silicon solar cell employing an oxide-charge-induced electron accumulation layer demonstrates complete suppression of the dark emitter recombination current JE to values so low that the base recombination current dominates in determining the open-circuit voltage VOC. This suppression of JE results in measured values of VOC considerably larger than those previously reported for n-on-p silicon solar cells. This ability to suppress JE leads to projections of efficiency of about 18% AM0 and about 20% AM1 for this oxide-charge-induced high-low-junction emitter (OCI-HLE) solar cell.
GaAs- (GaAl)As LOC-DBR laser with high differential quantum efficiency
Authors: Shams Mohammad Kazem , Wang Shyh
Published: February 2003

Operation of a LOC-DBR laser which exhibits high differential quantum efficiency is reported. It is shown that this result is obtained by further reduction of losses in the unpumped regions of the laser, especially, excessive absorption losses due to nonuniform Al carryover in the thin ’’GaAs’’ layer.
Effects of pinholes, oxide traps, and surface states on MIS solar cells
Authors: Green Martin A.
Published: February 2003

It is shown that the insulating layer in metal-insulator-semiconductor (MIS) solar cells by no means has to be perfect to obtain optimum photovoltaic performance. Oxide pinhole densities as large as 1000 cm−2 can be tolerated without degrading the device properties. Large densities of oxide traps at energies close to the majority-carrier band edge in the semiconductor can reduce the cell efficiency as can surface states in nonoptimal devices. Devices optimally designed with an inversion layer at the IS interface are virtually immune to these states, densities in excess of 1013 cm−2 causing no degradation in properties.
Annealing studies of Be-doped GaAs grown by molecular beam epitaxy
Authors: McLevige W. V. , Vaidyanathan K. V. , Streetman B. G. , Ilegems M. , Comas J. , Plew L.
Published: February 2003

Differential resistivity and Hall effect measurements and secondary ion mass spectrometry (SIMS) are used to study the annealing behavior of GaAs doped with high Be concentrations during growth by molecular beam epitaxy (MBE). The diffusion coefficient of MBE-grown Be in GaAs is determined to be (0.5–1) ×10−13 cm2/sec at 900 °C, a value which is two orders of magnitude lower than that for implanted Be of equal concentration [(2–3) ×1019 cm−3]. The concentration dependence of the diffusion of MBE-grown Be in GaAs is also observed to be substantially less than that for implanted Be. The implantation of He in Be-doped MBE layers to create lattice damage does not significantly affect the Be diffusion in a subsequent anneal.
Picosecond pulse generation with a cw GaAlAs laser diode
Authors: Ho P.-T. , Glasser L. A. , Ippen E. P. , Haus H. A.
Published: February 2003

We report the generation of 20-ps optical pulses at microwave repetition rate from a GaAlAs double-heterostructure diode operating cw at room temperature. The diode is operated in an external optical resonator and is actively modulated at 3 GHz. The pulses are measured by autocorrelation using SHG in LiIO3. They are the shortest pulses ever reported for a cw laser diode.
The influence of bulk nonradiative recombination in the wide band-gap regions of molecular beam epitaxially grown GaAs-AlxGa1−xAs DH lasers
Authors: Tsang W. T.
Published: February 2003

It is shown that bulk nonradiative recombination near the heterojunctions in the wide-band-gap regions is probably an important contributor to the higher threshold current densities of the best state-of-the-art molecular beam epitaxial GaAs-AlxGa1−xAs DH lasers over similar geometry liquid-phase epitaxial lasers. This recombination probably is at least part of the cause of the large recombination velocity (measured as interfacial recombination velocity) in molecular beam epitaxial heterostructures.
Characteristics of the electron-beam-controlled XeF laser
Authors: Champagne L. F. , Harris N. W.
Published: February 2003

Output power and efficiency for e-beam-controlled operation which is comparable to e-beam-pumped operation is reported. Under optimum conditions laser enchancements of 3.2 : 1 can be achieved in the presence of an applied electric field at an overall efficiency of ∼1.8%. In this mode of operation greater than 75% of the input energy to the gas is supplied by the sustainer. The concentration of NF3 is the most sensitive parameter for maintaining maximum output power, efficiency, and stable operation.
Optically pumped GaAs lasers with acoustic distributed feedback
Authors: Yamanishi M. , Ameda M. , Ishii K. , Kawamura T. , Tsubouchi K. , Mikoshiba N.
Published: February 2003

Experiments on a two-dimensional acoustic distributed feedback (ADFB) laser are described. A set of distributed Bragg reflectors (DBR’s) were formed on a GaAs crystal which was optically pumped at liquid-nitrogen temperature and an surface acoustic wave (SAW) at a frequency around 1.2 GHz was injected into the planar region between the DBR’s. We observed the oscillation of the two-dimensional ADFB modes. The SAW power, needed for the onset of the oscillation of the modes, was about 5 mW under the present experimental condition. Some discussions on its applications are briefly described.
Growth of metastable InSb1−xBix thin films by multitarget sputtering
Authors: Zilko J. L. , Greene J. E.
Published: February 2003

Metastable solid-solution polycrystalline InSb1−xBix films with InBi concentrations up to ∼12 mole% have been grown by multitarget sputtering. This exceeds the solid-solubility limit of 2.6 mole% InBi reported for melt-grown bulk InSb1−xBix. The films were deposited on substrates which rotated through separate InSb and Bi discharges maintained at an Ar pressure of 15 mTorr. The relative target voltages were used to control the composition of the deposited films and were chosen such that the deposition rate was always less than a monolayer per target pass. The film growth temperatures investigated were 135 and 165 °C and a (110) preferred orientation was obtained in films grown on Corning 7059 glass substrates. All solid-solution films were stoichiometric within the accuracy of our electron microprobe, ∼0.5 at.%. The incorporation probability of Bi was found to decrease with increasing Bi impingement flux and with increasing growth temperature. The films were n type with a net room-temperature carrier concentration increasing monotonically from 1017 to 1018 cm−3 with increasing InBi concentration. Precipitation of metallic Bi was observed in films containing greater than 12 mole% InBi.
Photoluminescence observation of swirl defects and gettering effects in silicon at room temperature
Authors: Nakashima Hisao , Shiraki Yasuhiro
Published: February 2003

Swirl defects are nondestructively observed in silicon using a photoluminescence profile taken at room temperature. A precise geometrical correspondence between the photoluminescence profile and swirl pattern is obtained. High photoluminescence intensity spots correspond to low defect density regions and vice versa. The usefulness of this method for evaluating silicon crystals is also confirmed by observing the gettering effects in oxidized epitaxial wafers where the back surface is ground.
Surface-acoustic-wave velocity in ion-implanted quartz at very low temperatures
Authors: Hartemann P. , Doussineau P. , Levelut A.
Published: February 2003

A behavior typical of amorphous solids has been observed at very low temperatures for a layer obtained by ion implanting a quartz substrate. A surface-acoustic-wave velocity variation has been measured between 0.9 and 6 K for crystalline and implanted quartz by building a 960-MHz delay line oscillator. The quartz substrate was implanted with helium ions at 95 keV. Over a limited temperature range, the velocity on the implanted surface is proportional to the logarithm of the temperature according to the off-diagonal interaction between the acoustic wave and a broad distribution of two level defects. An increase of the proportionality coefficient is produced by an annealing at 567 °C and it seems related to a decrease of the specific mass. Moreover, the defect density of states is smaller than that of vitreous silica.
Tamper temperature and compression from simultaneous proton and alpha-particle measurements in laser fusion experiments
Authors: Cover R. A. , Kubis J. J. , Mayer F. J. , Slater D. C.
Published: February 2003

The energy loss per unit path length for a charged particle incident on a spatially uniform isothermal Maxwellian plasma is a function of the temperature and density of the medium. Within this model the temperature and compression ρΔr of the tamper of a laser-driven microshell target can be accurately determined, in the absence of electrostatic acceleration, by the simultaneous measurement of the energy loss from 3.52-MeV α particles from D-T reactions and 3.02-MeV protons from D-D reactions.
The effect of interface arsenic domains on the electrical properties of GaAs MOS structures
Authors: Chang R. P. H. , Sheng T. T. , Chang C. C. , Coleman J. J.
Published: February 2003

Postgrowth annealing of plasma grown GaAs oxides in N2 and H2 result in very different electrical behaviors. By examining cross-sectioned specimens of these oxides with transmission electron microscopy, and correlating the observed structure with electrical measurements, it is demonstrated that metallic As at the oxide-semiconductor interface plays a significant role in determining the MOS characteristics.
Ion-bombardment-enhanced diffusion during the growth of sputtered superlattice thin films
Authors: Eltoukhy A. H. , Greene J. E.
Published: February 2003

A technique is presented for determining the enhancement in solid-state diffusion caused by low-energy ion bombardment. In this technique, superlattice films are grown under varying conditions of ion bombardment and the amplitude of the resulting composition modulation wave is determined by analyzing x-ray diffraction satellite peaks surrounding the central Bragg peaks. The amplitude is in turn related to the enhanced diffusion coefficient D* (x) which may be expressed as D*0 exp(−x/δ) where δ is a characteristic diffusion length of the ion-bombardment-produced defects. This approach was confirmed experimentally using InSb/GaSb superlattice structures grown by multitarget sputtering, each sample having equilayer thicknesses between 12 and 30 Å. D* was found to increase as the sputtering pressure was decreased. Measured values of D* averaged over the enhanced diffusion region were on the order of 10−17 cm2/sec compared to a thermal interdiffusion coefficient of approximately 10−22 cm2/sec at the film growth temperature of 250 °C.
The nonlinear mechanism leading to polarization echoes in some powdered materials
Authors: Kunkel H. P. , Kupca S. , Searle C. W.
Published: February 2003

The phase of the dynamic polarization echo with respect to the second driving pulse has been measured for several powdered materials. The mechanism for echo formation, in all the materials that were examined, was found to be an anharmonic oscillator interaction with a nonlinear amplitude-dependent frequency.
Refractive-index dispersion of garnet films derived from accurate measurement of film thickness
Authors: Sun M. J.
Published: February 2003

Refractive-index dispersion of magnetic garnet films of composition (YSmLuCa)3(GeFe)5O12 is reported in a wavelength range of 0.55–1.5 μ. The dispersion was calculated from the film’s optical interference data and thickness value which was accurately determined by the technique of thin-film optical waveguide measurement. The calculated index values at the interference fringe locations were fitted to a two-term Sellmeier formulation. The accuracy was estimated to be better than 0.3%.
Infrared excitation spectrum of thallium-doped silicon
Authors: Scott Walter , Schmit J. L.
Published: February 2003

The excitation spectrum of thallium-doped silicon has been measured in crystals doped to a level of 5×1016 Tl/cm3. The spectrum is characteristic of an effective-mass-like acceptor with an optical ionization energy of 0.246 meV. The peak optical cross section was estimated to be 2.6×10−17 cm2.
Generation of time-reversed optical wave fronts by backward-wave photon echoes
Authors: Shiren N. S.
Published: February 2003

It is shown that backward-wave photon echoes may be generated and the echo wave fronts are time reversed with respect to the first pulse of either a two- or three-pulse input sequence. Some comparisons are made with the four-wave degenerate parametric technique for generating time-reversed wave fronts.
Two-photon resonance-enhanced third harmonic generation in deuterium chloride
Authors: Kang M. H. , Nguyen V. T. , Chang T. Y. , Damen T. C. , Burkhardt E. G.
Published: February 2003

Two-photon resonance-enhanced third harmonic generation of CO2 laser radiation has been studied in DCl. The measurements of the phase-matched third harmonic signal in a DCl-CF4 mixture of 1 : 0.010 up to 5 atm show that the third-order susceptibility for DCl gas is substantially larger than that for the CO gas.
The optical absorption edge of single-crystal AlN prepared by a close-spaced vapor process
Authors: Perry P. B. , Rutz R. F.
Published: February 2003

We have prepared several thicknesses of ∼1 cm by ∼1 cm epitaxial single crystals of AlN with a ’’high temperature (∼1800 °C) close-spaced vapor transport’’ technique. These crystals have been grown both on (011̄2) and (0001) sapphire wafers. The optical absorption edge is measured at 300 K and for the first time at low temperature (5 K). This data is parametrized to include both reflection losses due to scattering off surface imperfections and contributions from impurity absorption bands. This parametrization technique is used to determine the band gap and the nature, direct or indirect, of the absorption edge. A value of 6.28 eV was found to be the best value of Eg(5 K) and the gap was found to be direct.
Axial laser heating of small-diameter theta-pinch plasmas
Authors: Hoffman A. L. , Lowenthal D. D. , Crawford E. A.
Published: February 2003

Small 5-mm-diam high-density 3×1017 cm−3 ϑ-pinch plasma columns 1-m long have been heated by intense long-wavelength laser radiation (10 μ) along their entire length. Refractive beam trapping has been achieved when laser heating begins during or before the ϑ-pinch implosion. Plasma temperatures have been increased from under 2 eV to maximum values of between 30 and 90 eV, in agreement with a MHD laser heating code.
Hydrogenation of evaporated amorphous silicon films by plasma treatment
Authors: Kaplan D. , Sol N. , Velasco G. , Thomas P. A.
Published: February 2003

It is shown that heat treatment in a hydrogen plasma of pure amorphous silicon films prepared by UHV evaporation yields a material with no observable dangling bond ESR signal. This material has electrical properties similar to films prepared by a glow-discharge decomposition of silane but a lower hydrogen content as deduced from ir absorption data.
Orientation effects in the LPE growth of GaInAsP quaternary alloys
Authors: Oe Kunishige , Sugiyama Koichi
Published: February 2003

It was found that the liquidus composition determined by the saturation technique for the (100) -oriented InP source crystal is different from that for the (111) B-oriented InP source crystal in the LPE growth of GaInAsP alloys. The lattice-matching conditions in GaInAsP LPE growth using the liquidus data are also influenced by the substrate orientation.
Theoretical analysis of thermal and mass transport in ion-implanted laser-annealed silicon
Authors: Wang J. C. , Wood R. F. , Pronko P. P.
Published: February 2003

Experimentally observed laser-induced redistributions of ion-implanted dopants in silicon are explained theoretically in terms of diffusion in the molten state. Calculations of thermal and mass diffusion in silicon show that the redistribution of a dopant file after pulsed-laser annealing is dependent on the time the dopant region remains molten and on the value of the mass-diffusion coefficient for the particular dopant.
Lattice vibrations of In1−xGaxAsyP1−y quaternary compounds
Authors: Pinczuk A. , Worlock J. M. , Nahory R. E. , Pollack M. A.
Published: February 2003

We report a Raman study of the lattice vibrations of the quaternary compound In1−xGaxAsyP1−y over the whole range of compositions lattice-matched to InP. The major bands in the spectra show a pseudo-two-mode behavior involving the optical phonons of InGaAs and InP. A low-frequency structure is attributed to disorder-induced scattering by acoustical vibrations. Weaker bands are assigned to Ga-P and In-As pair vibrations.
Pulsed frequency modulation of superconducting resonators
Authors: Birx D. , Dick G. J. , Little W. A. , Mercereau J. E. , Scalapino D. J.
Published: February 2003

Adiabatic frequency modulation of a superconducting resonator has been achieved by pulsed microwave interference. The technique has been shown to produce phase-coherent variable-frequency pulse-power gain.
Preparation of amorphous magnetic powder by atomization technique
Authors: Yamaguchi T. , Narita K.
Published: February 2003

The atomization technique, which is widely used for producing metallic powders in a large quantity, has been applied to the preparation of amorphous powder of Fe-Si-B alloys fairly successfully. The as-quenched powder consists of noncrystalline and crystalline portions. The fractional volume of the noncrystalline portion increases with decreasing particle size and exceeds 80% for 20-μ particles. The crystallization temperature of this powder is almost the same as that of the amorphous ribbon with similar composition.
A Schottky-barrier solar cell on sliced polycrystalline GaAs
Authors: Yeh Y. C. M. , Stirn R. J.
Published: February 2003

Antireflecting-metal-oxide-semiconductor (AMOS) technology has been applied to sliced wafers of polycrystalline GaAs having grain sizes of about 100 μm. Simulated AM1 sunlight efficiencies up to 14% were obtained, and studies using the scanning electron microscope showed that grain boundaries have minimal effect on short-circuit current density. However, current-voltage characteristics show some influence on open-circuit voltage.
Generation of time-reversed waves by nonlinear refraction in a waveguide
Authors: Jensen S. M. , Hellwarth R. W.
Published: February 2003

We have generated, essentially instantaneously, a time-reversed replica (phase-conjugate) of a monochromatic optical wave (at 6943 Å) by directing the wave into a CS2-filled waveguide where it interacts via the third-order nonlinear susceptibility with counterpropagating pump waves of the same frequency. This method is shown to have advantages over a similar replication process which has been observed with unguided waves in an infinite homogeneous medium.
Second-harmonic generation at 2660 Å in BeSO4⋅4H2O
Authors: Kato K.
Published: February 2003

Beryllium sulfate tetrahydrate (BeSO4⋅4H2O) has been found to be phase matchable for frquency doubling of 5321-Å radiation. The water white crystal is highly transparent from 1900 to 13 700 Å. The nonlinear optical constant was measured to be d36(BeSO4⋅4H2O) = (0.62±0.06) xd36(KD*P).
Magnetoresistance in yttrium iron garnet
Authors: LeCraw R. C. , Gyorgy E. M. , Wolfe R. , Bonner W. A. , Blank S. L. , Grodkiewicz W. H.
Published: February 2003

The magnetoresistance of bulk and epitaxial films of doped n-type yttrium iron garnet is reported for the first time. In (111) films a ΔR/R of −0.55% is observed as a saturating applied field H is rotated out of the (111) plane to the film normal. There is no observable change in ΔR/R as H is rotated in the (111) plane, with the current I in various directions in the (111) plane. This isotropy of ΔR/R in the (111) plane has not been observed in other ferromagnetic materials such as iron and nickel and is not understood as yet. The same isotropy in the (111) plane is also observed in bulk yttrium iron garnet. A possible use of this magnetoresistance for magnetoresistive detectors in magnetic bubble devices is discussed.
Determination of the recombination coefficient in CO2 laser discharges
Authors: Homann Ch. , Hübner H. , Bötticher W.
Published: February 2003

The effective recombination coefficient γ* in a self-sustained CO2 laser discharge at a pressure of 1.3 bar is determined from a rate equation for the electron density using experimental values of the discharge current and voltage. It is found that γ* depends strongly on the electric field strength as well as on the electron density.
Intense lasing in discharge excited noble-gas monochlorides
Authors: Sze Robert C. , Scott Peter B.
Published: February 2003

Intense lasing of XeCl (180 mJ) and KrCl (100 mJ) occurs using HCl as the halogen doner. The low energies obtained from e-beam devices are believed to result from Ar+2 molecular-ion absorption. Very long XeCl lasing lifetime with respect to gas fill is observed; this is postulated to be the result of photodissociation of Cl2 due to the laser wavelength which, in turn, results in enhanced rates for the formation of HCl.
Iron as a thermal defect in silicon
Authors: Weber E. , Riotte H. G.
Published: February 2003

Thermally treated silicon contains iron which can be frozen on interstitial sites by quenching. EPR, combined with neutron activation analysis of heat-treated and as-grown silicon, shows that the iron diffuses into the crystal from sources outside the specimen. It can be found mostly in the Td interstitial site. The untreated floating-zone silicon includes only 1013 Fe/cm3.
Broadly tunable dye-laser emission to 12 850 Å
Authors: Kato K.
Published: February 2003

Tunable dye-laser emission has been obtained up to 12 850 Å by pumping a dimethyl sulfoxide solution of a carbocyanine dye with an Nd : YAG laser. The solution lased in two distinct wavelength ranges of 11 070–11 870 and 11 920–12 850 Å depending on the dye concentration.
Diffraction-limited geodesic lens for integrated optics circuits
Authors: Chen B. , Marom E. , Morrison R. J.
Published: February 2003

A diffraction-limited geodesic lens was demonstrated in a polyurethane film-glass substrate waveguide structure. The lens has an aspherical depression and a rounded edge. The measured focal length remained at 10 mm up to 92% of the aperture. Diffraction-limited focal spot size was measured for an input beam width of 2 mm. For larger input beamwidth, the spot size measurement was limited by the optical resolution of the detection system.
High-efficiency prism coupler for optical waveguides
Authors: Sarid Dror , Cressman Paul J. , Holman Robert L.
Published: February 2003

A single prism has been used to simultaneously couple light into and out of an optical waveguide, with a guiding length of 1 cm. The method, which is simple and reproducible, utilizes two optimized gaps for the coupling regions. Coupling efficiencies in excess of 90% have been achieved.
An optical waveguide polarizer using dichroic absorption of M centers
Authors: Sasaki K. , Sasada T.
Published: February 2003

Dichroic absorption can be produced by orienting M centers in a NaF crystal. An optical waveguide adjustable polarizer is realized by using the NaF crystal as the top layer of a thin-film glass waveguide. The measured polarization ratios as a function of the guide length are compared with the theoretical calculations.
Time-resolved spectroscopy of the Ar* 2-excimer emission
Authors: Diegelmann M. , Wrobel W. G. , Hohla K.
Published: February 2003

High-pressure argon was excited by a 2-ns 600-keV e-beam pulse, and time integrated as well as time resolved fluorescence spectra were measured. No significant dependence of line center (126.2±0.1 nm) or spectral width (80±10 nm) of the Ar2 continuum on gas pressure was found in the range 0.5–20 bar. From the buildup time constant of fluorescence we calculated the three-body rate constant for Ar2 formation to be 5×10−33 cm6/sec. The fluorescence decay was found to consist of two exponentials with time constants 8.6 and 39.2 ns at 20 bar and 12.6 and 73.9 ns at 10 bar, respectively. We attribute this behavior to the fluorescence originating from the singlet and triplet upper state. From the spectral shift between the two components we determined the singlet-triplet splitting in the excited Ar2 molecule to be 12 Å corresponding to 760 cm−1.
Mechanism of performance limitations in heavily doped silicon devices
Authors: Redfield David
Published: February 2003

Proposed mechanisms for the observed performance limitations in heavily doped silicon transistors and solar cells are reexamined in detail. The physical-defect mechanism is ruled out by the uniformly negative results of new measurements of defects by x-ray topography and deep-level spectroscopy. Extensive analysis of the band-gap-narrowing mechanism discloses a number of flaws that rule it out also. As an alternative to these models, it is proposed that Auger processes in heavily doped regions of the devices are the dominant source of the observed limitations. An order-of-magnitude calculation for the solar-cell case leads to good agreement with the observed maximum open-circuit voltage.
Measurement of surface recombination velocity in semiconductors by diffraction from picosecond transient free-carrier gratings
Authors: Hoffman C. A. , Jarašiūnas K. , Gerritsen H. J. , Nurmikko A. V.
Published: February 2003

Direct measurement of surface recombination velocity has been achieved for n-InP, p-InP, and n-GaAs by a novel technique which is based on picosecond optical resolution of a transient diffraction grating, formed by an excess electron-hole plasma near the surface of the semiconductor. The influence of diffusion, bulk recombination, and surface recombination on the carrier density are included in the analysis of the experiment, which shows that the method is specifically sensitive to surface recombination velocity. Effects of the plasma density on the diffusion coefficient and the carrier lifetime are discussed.