bluuebunny/crossref_metadata_2025 huggingface dataset:
Auger profile study of the influence of lattice mismatch on the LPE InGaAsP-InP heterojunction interface
Authors: Feng M. , Cook L. W. , Tashima M. M. , Stillman G. E. , Blattner R. J.
Published: February 2003

Auger depth profiles of InGaAsP-InP heterojunctions grown by liquid phase epitaxial techniques under different lattice-mismatch conditions have been measured. Results are presented for samples with Δa/a less than ±0.03, and equal to +0.20 and −0.11% grown from solutions with XlGa=0.40%, XlP=0.36%, and XlAs=3.53, 3.78, and 3.40%, respectively. Only small differences in the chemical transition width of InP-InGaAsP and InGaAsP-InP interfaces (the last grown layer is listed first) have been observed when the lattice mismatch is less than ±0.03%. However, the width of the chemical transition region of the InP-InGaAsP interface increases more rapidly than that of the InGaAsP-InP interface as the lattice mismatch increases. This result can be understood in terms of the growth kinetics at the heterojunction interfaces.
Calculation of the dynamics of surface melting during laser annealing
Authors: Surko C. M. , Simons A. L. , Auston D. H. , Golovchenko J. A. , Slusher R. E. , Venkatesan T. N. C.
Published: February 2003

We present a thermal transport model to describe the melting and resolidification of semiconductors which is observed to occur during annealing with a pulsed laser. The temperature-dependent properties of both the solid and liquid are included. We compare this calculation with experimental results for the time duration of the melted surface for crystalline Si and Ge. The temperature of the liquid surface as a function of time is calculated and effects associated with the hot liquid and the vapor are also discussed.
Delay measurement of experimental 2.5-μm Josephson current injection logic (CIL)
Authors: Gheewala T. R.
Published: February 2003

Switching speeds of experimental Josephson interferometer circuits are measured on chains of current injection logic (CIL) gates fabricated using 2.5-μm minimum features. Logic delay of 32 ps per gate is measured for a four-input OR gate with a fan-out of 2. The average power dissipation of the four-input OR gate is 4 μW and the corresponding power-delay product is 1.28×10−16 J. For four-input AND gates the measured logic delay is 60 ps, the power dissipation is 6 μW, and the power-delay product is 3.6×10−16 J. The results are found to be in excellent agreement with estimates based on computer simulations.
High-average-power 16-μm gasdynamic CO2 laser using a multipass cavity
Authors: Wexler B. L. , Waynant R. W.
Published: February 2003

The performance of the 16-μm CO2 electric discharge gasdynamic laser has been investigated as a function of gas flow rates and the position of the optical axis. Using a five-pass optical cavity configuration and a high pulse repetition rate, a significant fraction of the energy available in the flow has been extracted. With the laser operating on both the 9.4- and 16-μm transitions in cascade, the maximum average output power at 16 μm was 5.4 W at 4800 Hz. Comparison with the 19.7 W generated at 9.4 μm indicates a 70% efficiency for the cascade process.
Electron trapping in neutron transmutation doped silicon
Authors: van Ruyven L. J. , Ammerlaan C. A. J.
Published: February 2003

The isochronal anneal of phosphorus in neutron transmutation doped silicon has been studied with electron paramagnetic resonance. It was found that the fraction of phosphorus atoms occupying a substitutional lattice site increases almost linearly in the range of anneal temperatures from 250 to 700 °C. Recovery of the Fermi level to the normal n-type position is observed to occur between 500 and 700 °C. It is proposed that phosphorus atoms are constitutent parts of the electron trapping centers, capable of trapping two electrons.
Facet protection of (AlGa)As lasers using SiO2 sputter deposition
Authors: Yuasa Tonao , Endo Kenji , Torikai Toshitaka , Yonezu Hiroo
Published: February 2003

Sputter-deposited SiO2 films on (AlGa)As DH laser facets were found by chemical erosion tests and Auger spectroscopy to have strong adhesion and an abrupt film-facet interface profile. Half-wave coatings by sputtering allowed stable long-term operation of lasers over several thousand hours at 10–20-mW (0.7–1.2 mW/μm) power levels at room temperature, almost without change from the initial value of threshold current and optical power.
Thin-film Mo-Si interaction
Authors: Schutz R. J. , Testardi L. R.
Published: February 2003

Previous results of single-crystal Si-Mo interaction indicate that MoSi2, the phase predicted by the Walser-Bené theory, is the first silicide to form at the Si-Mo interface. We now report that in thin-film Si-Mo diffusion couples either MoSi2 or a combination of Mo3Si/Mo5Si3 forms at the interface. These two results have never been observed to occur in the same sample, indicating a bistable growth mechanism. We believe this growth to be triggered by the initial interface which is modified by sample preparation conditions. Interdiffusion and reaction of Mo with amorphous Si is also found to be slower than with crystalline Si.
An MOS field-effect transistor fabricated on a molecular-beam epitaxial silicon layer
Authors: Katayama Y. , Shiraki Y. , Kobayashi K. L. I. , Komatsubara K. F. , Hashimoto N.
Published: February 2003

An MOS field-effect transistor which has a buried channel structure and operates in the depletion mode is first fabricated on a molecular-beam epitaxial silicon layer. The field-effect mobility of this MOSFET is comparable to those of the MOSFET’s fabricated on conventional single crystals of silicon.
Directional coupler switch in molecular-beam epitaxy GaAs
Authors: Carenco A. , Menigaux L. , Alexandre F. , Abdalla M. , Brenac A.
Published: February 2003

An 8-mm-long rib waveguide directional coupler has been made from a n (1×1016 cm−3) GaAs layer grown by molecular-beam epitaxy. By reverse biasing the ’’stepped Δβ’’ Schottky electrodes with less than 30 V, more than 17 dB power isolation has been achieved at 1.06 μm for both switching states. Improvements are expected with the progress in layers morphology and doping level. This is a new step towards the feasibility of optoelectronic devices by a growth technique which is very attractive for GaAs integrated circuits.
Zero temperature coefficient of delay for surface waves in quartz
Authors: Sinha B. K. , Tiersten H. F.
Published: February 2003

Some new orientations and propagation directions possessing zero temperature coefficients of delay for surface waves in quartz with somewhat better electromechanical coupling than the ST cut are reported. One of the orientations also exhibits an almost-zero power flow angle. The results have been obtained using a nonlinearly based formalism in which the reference geometry, which remains fixed as the temperature is varied, may be employed.
New sector-scan imaging devices
Authors: Haine F. , Bruneel C. , Torguet R. , Bridoux E.
Published: February 2003

A new sector-scan imaging device with moving focus is reported. This device uses an analog calculator for generating the scanning acoustic beam in place of the digital calculator needed in some other designs. It allows series or parallel operation in the imaging process. The basic principle and some preliminary results on the analog calculator operation and on imaging applications are shown.
Coupling to an ’’edge metal-oxide-metal’’ junction via an evaporated long antenna
Authors: Yasuoka Y. , Heiblum M. , Gustafson T. K.
Published: February 2003

The observation of planar long-antenna coupling to a metal-oxide-metal (edge configuration) has been demonstrated at λ=118 μm. The two major lobes of an 11λ antenna are coupled to via a superstrate prism. Insufficient data is presently available to identify with certainty the mechanism of detection.
Acceleration of solid pellets using a plasma gun
Authors: Buller T. L. , Turnbull R. J. , Kim K.
Published: February 2003

The use of solid pellets of hydrogen isotopes to refuel thermonuclear fusion reactors based on the tokamak configuration will require that the pellets be accelerated to high velocities. One possible method of acceleration is to interact a fast plasma from a plasma gun with the pellets. In this paper preliminary results are given on the acceleration of solid pellets with a plasma gun. The plasma-gun requirements for successful acceleration to high velocities are discussed.
High-temperature lifetesting of Al/SiOx/p-Si contacts for MIS solar cells
Authors: Godfrey R. B. , Green M. A.
Published: February 2003

High-temperature lifetesting of Al/SiOx (10–15 Å)/p-Si contacts for high-efficiency MIS solar cells is reported. Electrical degradation in the temperature range 270–400 °C was governed by an activation energy of 2.56±0.12 eV, indicating that the reduction of the thin oxide layer by Al was the mechanism responsible. Extrapolating to lower temperatures indicates that this process proceeds at a negligible rate below 200 °C.
The influence of preparation conditions on the hydrogen content of amorphous glow-discharge silicon
Authors: Milleville M. , Fuhs W. , Demond F. J. , Mannsperger H. , Müller G. , Kalbitzer S.
Published: February 2003

The hydrogen content in a-Si films prepared by the glow-discharge technique has been studied as a function of preparation conditions. From the γ-ray yield of the nuclear reaction 1H(15N,αγ)  12C we find hydrogen contents ranging from 4 up to 50 at.%, depending largely on the deposition temperature of the films. Depth profiles show that hydrogen is incorporated uniformly into the films.
New experimental evidence for minority-carrier MIS diodes
Authors: Tarr N. G. , Pulfrey D. L.
Published: February 2003

Measurements of short-circuit density Jsc and open-circuit photovoltage Voc have been made over a range of illumination levels at various temperatures for Al-SiOx-pSi MIS photodiodes. It is found that at high illumination levels the data satisfy the relation Jsc=J0 exp(qVoc/kT), where J0 is a temperature-dependent constant. By examining the variation of J0 with temperature it is conclusively demonstrated that the dark current in these diodes is dominated by minority-carrier flow, confirming recent theoretical predictions.
Intensity dependence of harmonic generation in 10-μm laser-produced plasmas
Authors: Baldis H. A. , Burnett N. H. , Enright G. D. , Richardson M. C.
Published: February 2003

Integral harmonic intensities in the radiation scattered from nanosecond 10.6-μm laser-target interaction have been studied as a function of laser energy and target orientation. Measurements suggest a power-law dependence of scattered harmonic intensity with increasing laser intensity, Inω0∝Inω0, up to ∼1×1014 W/cm2 incident with evidence of saturation above this level. The scattered harmonic light at 7ω0 was found to be fairly isotropic in front of the target.
Transverse magnetoresistance of highly doped n-type InSb in strong magnetic fields
Authors: Wu Chhi-Chong , Chen Anna
Published: February 2003

Quantum effects are being studied in the transverse magnetoresistance of degenerate semiconductors such as highly doped n-type InSb for the case where acoustic phonons are the dominant scattering mechanism. The result shows that the transverse magnetoresistance oscillates with the dc magnetic field owing to the degeneracy of the electron gas. However, the transverse magnetoresistance for nonparabolic bands is enhanced due to the strong magnetic field dependence.
Electrical properties of semiconductor-electrolyte (CdS-NiCl2) using surface acoustic wave techniques
Authors: Das P. , Webster R. T. , Davari B.
Published: February 2003

Spectroscopy of the cadmium sulphide–nickel chloride interface has been performed by measuring the acoustoelectric voltage induced by a SAW-delay line. Observation of transitions at different radiation wavelengths is attributed to the presence of electronic levels at the interface.
The detection of 300 °K blackbody radiation with Rydberg atoms
Authors: Gallagher T. F. , Cooke W. E.
Published: February 2003

Using selective field ionization (SFI) of Na Rydberg atoms we have detected the 300 °K blackbody radiation which induces the Na transitions 17s→17p, 18s→18p, 17d→18p, and 17d→18f frequencies of 27.3, 22.8, 7.4, and 41.6 cm−1, respectively. Investigation of the probable collisional effects show that they are negligible at 300 °K and allow us to project temperatures of <25 °K for Rydberg-atom long-wave detectors.
Nonlinear theory of degenerate four-wave mixing
Authors: Marburger John H. , Lam Juan F.
Published: February 2003

We report an exactly solvable theory of ’’time-reversed’’ phase-front generation including depletion effects and nonlinear phase distortion. Simple expressions are obtained for peak reflected signals with and without input probe signals.
An electro-optic tunable filter
Authors: Pinnow D. A. , Abrams R. L. , Lotspeich J. F. , Henderson D. M. , Plant T. K. , Stephens R. R. , Walker C. M.
Published: February 2003

This letter describes a tunable optical filter that couples light energy between ordinary and extraordinary polarizations in a birefringent electro-optic crystal at the phase-matched wavelength by means of a spatially periodic dc electric field. The specific embodiment described here is a LiTaO3 platelet operating with transverse electric field and located between cross polarizers. Analogies to both the S̆olc birefringent filter and the Harris acousto-optic filter are cited. The electro-optic filter is tuned by varying the spatial period of the electric field via an array of separately addressable finger electrodes. We have demonstrated tunability from 4700 Å to 4.5 μm. Experimental results of transmittance versus applied voltage and of bandwidth versus pass wavelength agree well with theory. The flexibility of this type of electronic filter in allowing synthesis of arbitrary transfer functions through nonperiodic voltage distributions is emphasized.
Multiple-pass CO2 laser heating of a ϑ-pinch plasma
Authors: Brooks R. D. , Watt R. G. , Pietrzyk Z. A. , Vlases G. C.
Published: February 2003

A 20-cm-long 3.6-cm-diam ϑ-pinch plasma is placed within a coupled optical cavity of a 40-J CO2 TEA laser as an active optical element. Ruby-laser scattering is used to measure the plasma temperature for the non-laser-heated, the single-pass, and the multiple-pass laser-heated plasmas. At times in the pinch cycle when holography shows a favorable density profile, multiple-pass heating equivalent to over five passes of the single-pass energy is observed.
A transient optical reflectivity study of laser annealing of ion-implanted silicon: Thresholds and kinetics
Authors: Liu Y. S. , Wang K. L.
Published: February 2003

By probing transient optical reflectivity, we have investigated the liquid phase epitaxial regrowth kinetics of ion-implanted silicon during laser annealing. For annealing of ion-implanted silicon with an 80-ns (FWHM) pulse of various intensities at 1.06 μm, the threshold energy density required for melting is observed to be a constant. Above this threshold value, annealing occurs via an amorphous-to-liquid-to-crystalline transition. Redistribution of As profiles as measured by He+ backscattering spectra is observed only when the incident energy density exceeds the threshold. Below this value, a reduction of dechanneled fraction is observed, but no dopant redistribution occurs. From the observed melting onset, a maximum heating rate of about 2×1010 deg sec−1 is observed.
Photoinduced optical anisotropy and color adaptation in silver-containing glasses
Authors: Borrelli Nicholas F. , Seward III Thomas P.
Published: February 2003

This paper reports photoinduced optical anisotropy (dichromism and birefringence) and color adaptation in oxide glasses containing silver and halogens. The effects are found in both photochromic and fixed-tint glasses. In certain of the photochromic glasses there is memory, such that after thermal fading redarkening by uv radiation reestablishes the anisotropic or color-adapted state. Dichroic ratios of 4 and birefringences of Δn=10−4 have been measured. The effects, similar to the Herschel and Weigert effects in silver halide photography, are explained on the basis of optical bleaching of anisotropically shaped submicroscopic aggregates of silver in contact with a silver halide.
Scanning-electron-beam annealing of arsenic-implanted silicon
Authors: Regolini J. L. , Gibbons J. F. , Sigmon T. W. , Pease R. F. W. , Magee T. J. , Peng J.
Published: February 2003

〈100〉 Si implanted with As (100 keV, 1015/cm2) was annealed with a scanning electron beam. The principal results obtained were (1) the electrical activity of the e-beam-annealed samples is the same as for control samples subjected to either cw laser annealing or thermal annealing at 575 and 1000 °C, respectively, for 30 min each; (2) recrystallization of the implanted layer as determined by MeV ion channeling and TEM measurements is complete; (3) the electron distribution obtained by stripping and van der Pauw measurements indicates that no diffusion of the implanted atoms has occurred. The annealing is therefore essentially identical to that obtained with a scanning cw laser.
Current dependence of spontaneous emission and of junction resistance as a test of the internal dynamics of injection lasers
Authors: Sommers H. S.
Published: February 2003

An expression is derived for the current dependence of spontaneous emission in the lasing state. It shows that the slope of the emission above threshold is controlled by a product of two terms, of which only one is affected by the dynamics of lasing. Since the other depends on subthreshold properties, the slope of the spontaneous characteristic is not a definitive test of laser models. While a rise in spontaneous emission above threshold is inconsistent with the linear rate equations describing the stimulated recombination, a strong saturation is not supportive of them. As an example, comparison of the properties of the laser of Paoli and Barnes, which exhibited a strong saturation, with data on other stripe units with various degrees of saturation shows that the unusually strong saturation they find is caused by an unusually low product of threshold current and external efficiency, not by a different form of the rate equation. As an aside it is shown that the slope ratio also measures the ratio of junction resistances above and below threshold.
Measurement of interface recombination velocity in (Pb,Sn)Te/PbTe double-heterostructure laser diodes
Authors: Kasemset Dumrong , Fonstad Clifton G.
Published: February 2003

The effective minority-carrier lifetime in the active region of Pb0.86Sn0.14Te/PbTe double-heterostructure (DH) laser diodes has been experimentally determined for a series of diodes with active-region widths ranging from 0.7 to 3.9 μm using a measurement technique which involves observing the dependence of the threshold current density on the duration of a current pulse input. From the data, it is inferred that the interface recombination velocity at the heterojunctions is as high as 1×105 cm/sec at 5 °K, while the bulk minority-carrier lifetime is 4.3 nsec. For a typical double-heterostructure laser with a 2-μm active-region width, this implies a reduction in the internal quantum efficiency due to interface recombination of as much as 80%.
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u measurements of photoluminescence intensities from cleaved (110) surfaces of n-type InP in a vacuum and gas ambients
Authors: Suzuki Tohru , Ogawa Masaki
Published: February 2003

The cause of remarkably strong photoluminescence (PL) intensity from (110) surfaces of n-type InP was investigated by in situ measurements of PL intensity in a vacuum of 4×10−7 Torr and in various ambients. The surface cleaved in the vacuum showed about 10 times lower intensity than that for the surface cleaved in air. The strong PL intensity cleaved in air was ascribed to a reduction of surface recombination velocity due to adsorption of H2O and/or O2 molecules onto the intrinsic surface. The strong PL intensity for surfaces cleaved in air, O2, and wet N2 were more or less unstable and decreased under photoexcitation. Normalized surface recombination velocity for the surface cleaved in air was ζ≲1, which was much less than that for GaAs (ζ≳10).
Electroluminescence efficiency profiles of Mn in ZnS ac thin-film electroluminescence devices
Authors: Marrello V. , Onton A.
Published: February 2003

We report a direct measurement of relative Mn electroluminescence (EL) efficiency in an ac EL device as a function of position normal to the ZnS film plane. The Mn EL efficiency decreases strongly with distance from the cathodic to anodic region of the ZnS layer. The cathodic-to-anodic efficiency ratio is about two orders of magnitude. In addition, the first ∼0.2 μm of ZnS deposited exhibits a significantly lower Mn EL efficiency relative to the remaining ZnS.
Elinvar-type behavior in the alloy Fe78Mo2B20
Authors: Tyagi S. , Lord A. E.
Published: February 2003

The ferromagnetic metallic glass alloy Fe78Mo2B20 exhibits Invar-type behavior in the amorphous state below approximately 250 °C. This behavior disappears upon crystallization. By thermal treatment of the amorphous alloy, excellent Elinvar-type characteristics have been obtained in partly crystallized Fe78Mo2B20 in the temperature range 20–300 °C.
Radiation from beam-plasma interaction in the presence of a dc field
Authors: Leboeuf J. N. , Tajima T.
Published: February 2003

Enhanced conversion of beam energy to wave energy and radiation by a dc electric field (Edc) when Edc<Ecr, a collective threshold dc field, is observed in a computer simulation. A significant improvement of the efficiency of traveling wave tubes and klystrons should result from this effect.
Pulsed-laser annealing of implanted layers in GaAs
Authors: Tandon J. L. , Nicolet M.-A. , Tseng W. F. , Eisen F. H. , Campisano S. U. , Foti G. , Rimini E.
Published: February 2003

Semi-insulating Si-implanted GaAs has been irradiated by a ruby-laser pulse (λ=0.694 μm, tp=15 ns) without using an encapsulant. Hall-effect measurements indicate that the values of sheet resistance, effective sheet electron concentration, and effective electron mobilities are roughly comparable to those of conventionally annealed samples. TEM micrographs show a difference in the defect structure after these two types of annealing.
Single Te films and Te trilayers for optical recording
Authors: Blom G. M.
Published: February 2003

The optical-recording characteristics of Te-trilayer structures are compared to those of single Te films on PMMA substrates. The results demonstrate that the single Te films are more sensitive using optical pulses ranging from 25 to 500 nsec, with otherwise identical recording and readout characteristics. A thermal analysis of the optical structures confirms such a sensitivity behavior.
Thermochemical coloration and annealing of spinel and magnesium oxide
Authors: White G. S. , Lee K. H. , Crawford J. H.
Published: February 2003

Heating spinel (MgAl2O4) single crystals in aluminum or magnesium metal vapor at temperatures in excess of 1800 °C results in the introduction of an optical absorption band at 5.3 eV. The same band can be produced by heating in a strongly reducing atmosphere with no metal vapor at 2100 °C. These results strongly support the suggestion of Bunch that the 5.3-eV band, created by atomic displacement collisions resulting from energetic particle bombardment, is associated with an F-type center. Isothermal annealing of the 5.3-eV band in MgAl2O4 and the 5.0-eV band in MgO introduced by thermochemical coloration suggests that the activation energy for oxide-ion vacancy motion is, respectively, 1.8 and 3.4 eV.
Preparation and properties of CuInS2 thin films produced by exposing sputtered Cu-In films to an H2S atmosphere
Authors: Grindle Steven P. , Smith Charles W. , Mittleman Steven D.
Published: February 2003

CuInS2 thin films have been made from copper, indium, and hydrogen sulfide gas using a two-step technique which involves exposing Cu-In films produced by sputtering pure copper and pure indium to H2S gas diluted with argon. X-ray diffraction, Auger electron spectroscopy, optical transmission, and electrical measurements were used to identify and characterize the CuInS2. The resulting films were all p type with resistivity in the range 0.1–500 Ω cm and showed a preferred orientation of the (112) plane parallel to the substrate.
The use of SnTe as the source of donor impurities in GaAs grown by molecular beam epitaxy
Authors: Collins Douglas M.
Published: February 2003

The use of SnTe as a source of donor impurities in the growth of n-type GaAs by molecular beam epitaxy (MBE) is investigated. Net carrier concentrations n between ∼1015 and ∼1018 cm−3 have been obtained with corresponding mobilities of ∼38 000 and 2100 cm2 V−1 sec−1 at 77 °K. Sharp changes in donor concentration have been obtained with no evidence for Sn accumulation at the surface. However, at higher donor concentrations (∼1018 cm−3) Te is found to accumulate at the surface.
Ion-electron (configurational) interface states in MOS structures
Authors: Kamieniecki E.
Published: February 2003

A new model of the semiconductor-insulator interface states is proposed. Transitions between free and bound states of a system consisting of a charged center in the insulator and an electron in the semiconductor are considered in the model. By assuming that the charged centers are located at different distances from the interface, the occurrence of a continuous distribution of Si/SiO2 interface states over the band gap of the semiconductor and the sharp decrease of the electron capture cross section as the binding energy of the states tends towards the conduction band edge are explained.
Acoustic microscopy of polymer materials
Authors: Wilson Robert G. , Tucker Paul A.
Published: February 2003

Reflection acoustic microscopy has been used to study polymer materials. Acoustic micrographs of polypropylene spherulites show branching and irregular growth of radial fibrils and a more three-dimensional interpenetrant nature of the impinging spherulites than does light microscopy. Acoustic micrographs of drawn polypropylene spherulites reveal inhomogeneous destruction of the original spherulites and light and dark contour bands, much like Newton’s rings, that are useful for monitoring thickness uniformity and internal structure of polymer film fabrication.
The mechanism of energy decrease in the XeBr laser
Authors: Balog George , Sander Robert K. , Seegmiller Emma
Published: February 2003

The xenon bromide discharge laser utilizes the reaction of Xe* with HBr to produce XeBr* in a dilute mixture with He or Ne buffer gas. XeBr lasers previously reported suffer from a high gas usage rate under static fill conditions. This is caused by the decomposition of HBr in the laser discharge to bromine and hydrogen. This reaction can be reversed using a catalyst in an external gas circulating system. We demonstrate a tenfold reduction in the consumption of the laser mix, namely 126 shots per liter of gas mix for decay of laser energy to 75% of maximum.
Molybdenum trioxide (MoO3)/silicon photodiodes
Authors: Osterwald C. , Cheek G. , DuBow J. B. , Verneker V. R. Pai
Published: February 2003

Molybdenum trioxide (MoO3) has been deposited onto single-crystal p-type silicon by neutralized ion-beam sputter techniques. The results indicate that the diode behavior is a function of oxygen partial pressure during the reactive sputtering. Film thickness, deposition rate, index of refraction, resistivity, and integrated transmission have been measured under AM1 illumination. It appears that thin films of MoO3 could serve as an n-type transparent semiconductor for photovoltaic applications.
Search for shell disintegration in laser implosion experiments
Authors: Tanaka K. , Thorsos E. I.
Published: February 2003

The possibility of shell disintegration in thin-wall targets as indicated by mixing of target surface material into the compressing core in laser-induced implosions has been investigated. Aluminum coated glass microballoon targets were irradiated by a two-beam Nd:phosphate glass laser with laser power up to 250 GW on target. The occurrence of mixing in these exploding pusher implosions was determined by using spatially resolved x-ray spectroscopy. Mixing was not observed except for laser shots with an intentional prepulse (∼10 mJ, 1.5 nsec before the main pulse).
Thin film characterization by atom probe field ion microscopy
Authors: Krishnaswamy S. V. , Messier R. , Ng Yee S. , Tsong T. T.
Published: February 2003

We have demonstrated that the atom probe field ion microscope (APFIM), with its resolution and single atom detection capability, is a potentially valuable thin-film characterization tool for both structural and compositional analysis. APFIM results for a range of thin films deposited onto Mo FIM tips by rf sputtering show details of void network structures, local ordering in amorphous materials, and atomic clustering effects. For instance, large (∼100–300 Å diameter) isolated voids are seen in WO3 and Ge films while smaller (∼10–100 Å) interconnected voids appear in the metallic films investigated (Ni, Pt, Au). Layer-by-layer depth profiling of atomic structure and selected area (10–30 Å diameter) compositional analysis for each layer are possible by pulse evaporation. From these latter experiments the existence of ion clusters is clearly established.
Weak field magnetoresistance skewness imposed by magnetic field
Authors: Kyriakos D. S. , Economou N. A.
Published: February 2003

The effect of a magnetic field on any crystalline material is to introduce an anisotropy in the electric resistivity. This letter examines the anisotropy which appears in the (001) plane of cubic crystals. Compact formulas are developed which show that in general the extreme values of the resistivity occur in directions which differ from those of the crystallographic axes. We thus demonstrate the existence of magnetoresistance skewness, as defined in recent papers of Allgaier et al., but have analyzed the phenomenon from a point of view which is complementary to that employed in the earlier work.
The use of ZnO in transparent type MIS solar cells
Authors: Petrou P. , Singh R. , Brodie D. E.
Published: February 2003

The efficiency of transparent type MIS solar cells is often below the theoretical estimate due to the simultaneous requirement that the thin metal film have good transparency and high conductivity. In this letter we report the properties of ZnO on Ti as a combined transparent conducting (TC) layer which can be used to reduce the sheet resistance of the thin metal layer.
Photoluminescence from hydrogenated ion-implanted crystalline silicon
Authors: Pankove J. I. , Wu C. P.
Published: February 2003

Ion-implanted crystalline silicon annealed in atomic hydrogen photoluminesces at 0.99±0.01 eV in a band having a spectral width of 0.1 eV FWHM. The emitted spectrum does not depend on the chemical nature of the implanted ion (Al, As, D, F, H, Ne, P, Si); however, when the surface is amorphized, a spectrum characteristic of hydrogenated amorphous Si is obtained.
Electron energy loss spectroscopy studies of the Si-SiO2 interface
Authors: Adachi T. , Helms C. R.
Published: February 2003

We have performed, for the first time, measurements of the electronic structure of the Si-SiO2 interface with electron energy loss spectroscopy (ELS) in connection with argon-ion sputtering. We have measured the depth profiles of both the 5.1- and 7.2-eV ELS peaks, which have been previously observed for both the Si surface with oxygen adsorbed and SiO2 with defects present. We have found that the intensities of these peaks, especially that of the 5.1-eV peak, show a maximum at the Si-SiO2 interface. This suggests that these ELS peaks come from special bonding configurations characteristic of the connective layer between Si and SiO2 at the interface.
The effect of an inhomogeneous bias field on the delay characteristics of magnetostatic forward volume waves
Authors: Tsutsumi Makoto , Masaoka Yoshihiko , Ohira Takashi , Kumagai Nobuaki
Published: February 2003

The delay and loss characteristics of magnetostatic forward volume waves in a YIG slab have been studied experimentally where an inhomogeneous bias field is applied normal to the slab surface by using artificially designed magnetic pole pieces. The nondispersive group delay characteristics with a low propagation loss are observed.
Soft x-ray and vacuum-ultraviolet spectroscopy of ion-beam-heated thin targets
Authors: Burns E. J. T. , Johnson D. J. , Farnsworth A. V. , Kuswa G. W. , Doschek G. A. , Feldman U.
Published: February 2003

XUV spectroscopy utilizing a 1-m grazing incidence spectrograph and photoelectric diodes is used to determine the response of approximately one-proton-range-thick planar targets to an intense beam of hydrogen and carbon ions. Electron temperature, brightness temperature, and total radiated power are then compared with radiation-hydrodynamic calculations to determine the ion-beam energy deposition and incident current density. Incident current densities of 25–35 kA/cm2 with 80% proton current and 20% singly ionized carbon ion current are consistent with the spectroscopic measurements.
Selection of high-power nanosecond pulses from large-aperture CO2 oscillators
Authors: Apollonov V. V. , Corkum P. B. , Taylor R. S.
Published: February 2003

A high-contrast 6-J 3-ns pulse has been obtained from an injection mode-locked TEA CO2 oscillator using an extracavity SF6-He saturable absorber to suppress the prepulse energy to <1 μJ and an intracavity semiconductor transmission switch to suppress postpulses. The techniques described in this paper will allow the frequency and transverse-mode control of an oscillator to be maintained to much higher powers than are presently possible.
Very-low-noise silicon avalanche photodiodes made by the channeling of aluminum in 〈110〉 silicon
Authors: Smeets E. T. J. M. , Politiek J.
Published: February 2003

A silicon n+pπp+ reach-through avalanche photodiode is described, where the p region is made by the channeling of aluminum atoms in 〈110〉 silicon. Effective noise factors of about 0.01 have been realized. The influence of the channeling on device parameters is discussed.
Effect of nonlinear index changes on degenerate four-wave mixing
Authors: Marburger John H. , Lam Juan F.
Published: February 2003

Unavoidable refractive-index changes induced by the pump beams in DFWM reduce the gain and shift its spectral pass band when the forward and backward pump intensities are unequal. The full linearized DFWM equations also imply large non-phase-conjugate signals in a collinear geometry. These effects influence the onset and spectrum of ’’spontaneous oscillation.’’
Efficient conversion of surface acoustic waves in shallow gratings to bulk plate modes
Authors: Melngailis John , Haus H. A. , Lattes A.
Published: February 2003

Nearly 100% conversion of surface acoustic waves to bulk plate modes via gratings has been observed and characterized. The gratings constructed on YZ LiNbO3 had 200 grooves of 20-μm period and 0.47-μm depth. Surface acoustic waves with wavelengths near 20 μm were normally incident on the gratings. At selected frequencies, determined by a phase velocity matching condition, nearly the entire surface wave signal was converted to bulk plate modes. In an identical grating on the opposite crystal face the signal was converted back to a surface wave. This transmission of signal from front to back of a crystal occurred at selected narrow (∼0.1%) bandwidths and with a loss of less than 0.5 dB in some cases. A theory has been developed which can predict the resonant frequencies and the transmission coefficient. Possible low-loss narrow band filter structures are considered.
Growth of dislocations during laser melting and solidification
Authors: Narayan J. , Young F. W.
Published: February 2003

Silicon crystals containing dislocations which terminated in the free surface were melted to depths of about 0.5 μm by rube-laser pulses, and the growth characteristics of dislocations of various types were studied by transmission electron microscopy. It was found that both edge- and screw-type dislocations grew in 〈113〉 directions that were not normal to the crystal-growth interface.
Influence of spin density in implanted Si layers on pulsed-laser annealing
Authors: Murakami K. , Ikawa E. , Gamo K. , Namba S. , Akasaka Y. , Masuda Y.
Published: February 2003

In order to clarify an influence of the spin density or the optical absorption coefficient on the pulsed-laser annealing effect, we have performed systematically ion-backscattering and channeling analysis and ESR measurement as a funcion of spin densities in ion-implanted Si samples. It was found that the spin density can yield a good criterion for predicting the annealing effect because the spin density is strongly correlated with the optical absorption coefficient. From spin-density measurements, the initial absorption coefficient of the as-implanted Si layer was found to be a very important factor which dominates the effect of laser annealing even if there is a nonlinear absorption mechanism.
Current conduction in Cr-MIS solar cells on single-crystal p-silicon
Authors: Rajkanan K. , Anderson W. A.
Published: February 2003

New information has been obtained about the current conduction in Cr-MIS solar cells by studying their current-voltage relationship over a wide range of temperatures. It is demonstrated that majority-carrier tunneling over the combined barrier due to the interfacial oxide and the space-charge region dominates the I-V characteristics at temperatures below 250 °K for Cr-SiOx- (p-Si) solar cells. Insight about the shunt resistance and back-contact barrier is also obtained by plotting the activation energy versus applied bias. Majority carriers tunneling via interface states control the characteristics at higher temperatures for these devices, made on 0.4-Ω cm p-silicon.
InGaAsP/InP distributed-feedback injection lasers fabricated by one-step liquid phase epitaxy
Authors: Doi A. , Fukuzawa T. , Nakamura M. , Ito R. , Aiki K.
Published: February 2003

Fabrication and lasing characteristics of InGaAsP/InP distributed-feedback injection lasers are described. An InGaAsP active layer, a p-InP clad layer, and an n-InGaAsP cap layer are successively grown on an InP substrate with a 0.32-μm periodic corrugation. The diodes emit at a wavelength of 1.1 μm up to 170 K under pulsed operation. Single longitudinal mode oscillation and a small temperature dependence of the lasing wavelength of 0.054 nm/K are obtained in these diodes.
Interference gratings blazed by ion-beam erosion
Authors: Johnson L. F. , Ingersoll K. A.
Published: February 2003

The use of ion-beam erosion to transform rounded symmetric grating relief patterns into asymmetric profiles with planar facets and sharp angular features is described. Calculated profiles are confirmed by experimental profiles produced in GaAs but with significant modifications caused by redeposition. Higher efficiency interference (holographic) gratings for spectroscopic and integrated optics applications are suggested by these results.
Chemical production of vibrationally excited HBr for a continuous wave laser
Authors: Miller Donald J. , Shackleford William L. , Emanuel George
Published: February 2003

Bromine has been added to the hydrogen cavity fuel of a cw supersonic mixing HF chemical laser. The hydrogen atoms produced in the F+H2→HF(v⩽3)+H reaction are used to continuously produce vibrationally excited HBr by the reaction H+Br2→HBr(v⩽6)+Br. Infrared chemiluminescence measurements indicate unsaturated gain coefficients of about (2±1) ×10−3 cm−1 for J=4 through J=8 for v=3, 2, and 1 levels of HBr. The current 3-cm gain length is not sufficient for lasing without the use of high-reflectivity mirrors, but a scaling to 18-cm gain length would be appropriate for a cw HBr chemical laser operating in the 4.0- to 4.5-μm region.
Kinetics of the thermal oxidation of WSi2
Authors: Mohammadi F. , Saraswat K. C. , Meindl J. D.
Published: February 2003

The thermal oxidation WSi2 films has been studied. Thin films of WSi2 were deposited by sputtering on (100) silicon and on oxidized silicon, and then oxidized in dry O2 and in steam atmospheres at 1000, 1100, and 1200 °C for times up to 30 min. In all cases the dry O2 oxidation resulted in films of poor quality. The films had rough surfaces, with WO3 present in powder form. However, steam oxidation gave SiO2 films of good quality. For WSi2/Si as well as WSi2/SiO2/Si samples, as the oxidation proceeded, WSi2 reacted with steam to form SiO2 and W5Si3. The rate of oxidation and activation energy were different for the two types of substrates. For WSi2 films deposited directly on Si, the oxidation process was significantly modified because Si atoms rapidly diffused through the silicides and took part in the oxidation process, and thus affected the conversion of WSi2 to W5Si3. However, with WSi2 films deposited on oxidized Si, the absence of free Si atoms resulted in the faster transformation of WSi2 into W5Si3.
Photoacoustic signal changes associated with variations in semiconductor crystallinity
Authors: McClelland J. F. , Kniseley R. N.
Published: February 2003

A photoacoustic (PA) signal dependence on Si crystal quality has been observed. The signal behavior has been investigated and on the basis of present evidence appears consistent, under conditions described in the letter, with PA theory as recently extended to include two-layer systems. Results of this study have potential use in laser annealing applications because they may provide a means of rapidly evaluating the degree of recrystallization, using the annealing laser beam set at a lower power level for PA excitation.
Dynamic behavior of mode-locked Nd : YAG laser annealing in ion-implanted Si, GaAs, and GaP
Authors: Murakami Kouichi , Gamo Kenji , Namba Susumu , Kawabe Mitsuo , Aoyagi Yoshinobu
Published: February 2003

By measuring the time-dependent optical reflectivity, we have investigated the dynamic behavior of annealing with the 30-psec pulse train of a mode-locked Nd : YAG laser. It was first observed that at narrow ranges of high laser energy density, the reflectivity of implanted Si and GaAs increases slowly to the level consistent with liquid ones, except GaP, and remains at that level for a period less than 200 nsec. As to Si, the mode-locked laser is confirmed to have a weak effect on temperature rise and, therefore, to produce a thin molten layer compared to Q-switched Nd : YAG lasers.
A new sensitive microwave bolometer heterodyne receiver
Authors: Nimtz G. , Schlicht B. , Lehmann H. , Tyssen E.
Published: February 2003

Some narrow-gap mixed crystal semiconductors show a magnetic field induced transport anomaly at low temperatures. The anomaly is accompanied by a transition from a low to a high resistivity state, which in turn causes a strongly nonlinear I-V characteristic. We have investigated microwave mixing near such a phase transition in n-type Hg0.8Cd0.2Te with a frequency of 37 GHz at 1.5 K and in magnetic fields up to 8.5 T. The sensitivity characteristic was measured and the responsivity determined to be about 15 times higher than that of a hot-carrier InSb bolometer. The time resolution of this new bolometer (=10−7 s) was slightly better than in InSb.
Electric field induced bend-undulation instability in a ferroelectric smectic C
Authors: Clark Noel A.
Published: February 2003

A new electric field induced mechanical instability of a single domain ferroelectric smectic C liquid is proposed. Threshold conditions and small and large field limits are discussed.
The growth of a GaAs VPE layer with an abrupt doping profile
Authors: Komeno J. , Ohkawa S.
Published: February 2003

A technique for achieving the growth of GaAs VPE layers with a highly abrupt doping profile is described. With this technique, the steepness of doping profile is remarkably improved and typical interface widths for the drop in carrier concentration from 1×1016 to 1×1015 cm−3 are 1000 Å. This technique also permits the growth of GaAs VPE layers with multistructure having a periodic Lo-Hi carrier concentration profile.
Laser annealing of self-ion damaged silicon
Authors: Foti G. , Campisano S. U. , Baeri P. , Rimini E. , Tseng W. F.
Published: February 2003

Partially damaged self-ion implanted Si(100) has been irradiated by a ruby laser pulse (λ=0.69 μm, tp=15 ns). Channeling effect technique measurements and TEM micrographs show the reordering of the implanted layer in the laser energy range 1.5–2.5 J/cm2. No polycrystalline transition has been detected. Calculations in terms of local melting of the disordered zone explain the experimental data.
Grain boundary states and varistor behavior in silicon bicrystals
Authors: Seager C. H. , Pike G. E.
Published: February 2003

The energy density of states in a Si grain boundary has been quantitatively determined for the first time. Since the deconvolution scheme used in this determination is a technique previously unapplied to real materials, the applicability of the model and the validity of the results were experimentally verified by comparing conductance and capacitance data. Additionally, a high-voltage varistor characteristic (highly non-Ohmic current) was observed. This shows for the first time that a simple grain boundary without intergranular additives is capable of a strong varistor behavior (nonlinearity coefficient α≳20).
Mode locking of traveling-wave cw ring dye laser
Authors: Blit S. , Tang C.L.
Published: February 2003

A synchronously pumped cavity-dumped mode-locked cw dye laser using a ring cavity configuration is reported. High intracavity intensities and reliable mode locking are achieved when the ring laser is operated in a unidirectional traveling-wave mode using an intracavity Faraday rotator. The experiment points up the importance of increaseing the asymmetry in the gain or loss between the two possible counterpropagating intracavity pulses in achieving good mode locking.
Thermal decomposition kinetics of AsF5-doped polyacetylene in vacuum
Authors: Inoue T. , Osterholm J.-E. , Yasuda H. K. , Levenson L. L.
Published: February 2003

Electrical conductivity measurements, mass spectra of desorbing species, and ESCA surface analysis are reported for AsF5-doped polyacetylene heated between 50 and 130 °C in vacuum. All measurements indicate first-order decomposition kinetics with activation energies between 13 and 20 kcal mole−1. Decomposition leads to the desorption of AsF3 and F2. Metallic arsenic remains in the polyacetylene as a decomposition by-product.
Anthraquinoide red display cells
Authors: Van Uitert L. G. , Zydzik G. J. , Singh S. , Camlibel I.
Published: February 2003

Anions of anthaquinones can form highly colored salts reversibly in response to an applied potential. These electrochromic materials may be used in display devices that have good stability and an efficiency as high as 250 cm2/C. Some cells can be color modulated at less than 0.10 V. Others have a sharp threshold for color modulation near 1.5 V and may be suitable for multiplexing.
Shallow-homojunction GaAs cells with high resistance to 1-MeV electron radiation
Authors: Fan John C. C. , Chapman Ralph L. , Bozler Carl O. , Drevinsky Peter J.
Published: February 2003

We have recently reported the fabrication of single-crystal GaAs shallow-homojunction solar cells that have conversion efficiencies of about 20% at AM1 (17% at AM0). These cells employ an n+/p/p+ structure, prepared by chemical vapor deposition on either GaAs or Ge substrates. We have now demonstrated the superior resistance of such cells to 1-MeV electron radiation, which produces effects approximating those due to space radiation. The experiments were done on four cells at fluences up to 1016 e/cm2. One of the cells was found to have both higher initial and final maximum power per unit area than any space cells previously reported.
Extension of the operating period of an UV Cu I
I laser by admixture of argon
Authors: Auschwitz B. , Eichler H. J. , Wittwer W.
Published: February 2003

The operating period of an UV Cu II laser (discharge current ≳25 A, duty cycle 6:1) is extended from minutes to over one hour by an admixture of 0.1% argon to the neon pump gas. In addition, a new laser line at 270.1 nm has been observed.