bluuebunny/crossref_metadata_2025 huggingface dataset:
Helical propagation of flux jumps
Authors: Boyer R. , Bussière J. F. , LeBlanc M. A. R.
Published: February 2003

Evidence is presented that flux avalanches are azimuthally asymmetric and propagate helically along axially magnetized wires of type-II superconductors carrying a conduction current. The variation of the velocity and helicity of propagation with conduction current is investigated. The helical trajectories are compared with the configuration of the magnetic induction in the vicinity of the surface.
X rays produced during ion implantation
Authors: Lurio A. , Ziegler J. F.
Published: February 2003

We have investigated the x rays produced when ion beams of B+, P+, and As+ are implanted into silicon over the ion energy range 20–2800 keV. The production of Si(L) x rays at 134 Å is very intense. These low-energy x rays are found to be very useful as a dose monitor when charge integration is not feasible; for example, for very low doses (<1012/cm2) and for neutral beam implantation (for currents above 2 mA).
Switching and oscillation phenomena in SnO2-VOx-PdO ceramics
Authors: Taketa Yoshiaki , Furugochi Ryoichi
Published: February 2003

Switching and oscillation were found in SnO2-VOx-PdO ceramics. This switching does not appear above 60°C. However, under 40°C, it comprises two switching actions and depends upon the ambient temperature. The oscillation is irregular and the amplitude is as great as 30−40 V at room temperature.
Direct observation of the dynamics of picosecond-pulse optical breakdown
Authors: Anthes John P. , Bass Michael
Published: February 2003

The dynamics of electron avalanche breakdown induced by picosecond laser pulses were observed directly with an ultrafast streak camera. The ionization rate for fused quartz exposed to a 25-psec 532-nm pulse which produced a damaging breakdown is ⩾4.5×1012 sec−1.
n-CdS/n-GaAs voltage-enhanced photoanode
Authors: Wagner Sigurd , Shay J. L.
Published: February 2003

We report an n-CdS photoanode grown on an n-GaAs substrate. The photovoltage at the n-GaAs/n-CdS junction in series with the CdS/electrolyte junction increases the solar-cell efficiency by a factor of about 1.5 relative to a simple n-CdS photoelectrochemical solar cell.
Efficient sprayed In2O3 : Sn n-type silicon heterojunction solar cell
Authors: Manifacier J. C. , Szepessy L.
Published: February 2003

We present results concerning In2O3 (tin-doped) n-type silicon heterojunction solar cell. The transparent and conductive In2O3 : Sn layer was made using a very simple, cheap, and quick method. Conversion efficiency up to 10% is reported. Typical parameters under AM1 simulated sunlight are open-circuit photovoltage Voc=500 mV, short-circuit photocurrent Isc=32 mA cm−2, and fill factors around 0.6–0.65.
Degradation of photoluminescence intensity caused by excitation-enhanced oxidation of GaAs surfaces
Authors: Suzuki Tohru , Ogawa Masaki
Published: February 2003

Rapid degradation of photoluminescence (PL) intensity under high excitation level (∼1 kW/cm2) was observed at fresh surfaces of GaAs crystals made by various growth methods. The Auger analyses showed quick oxide formation at the photoexcited GaAs surfaces. The degraded PL intensity was recovered by etchings only the oxide layers; thus, the cause of PL degradation was ascribed to the increase of nonradiative recombination at the oxide-GaAs interface. The oxidation process was proved to be athermal. In contrast to GaAs, Al0.3Ga0.7As and InP showed no or slow degradations, respectively, under the same excitation condition.
A new hypothesis on ultrasonic interaction with nematic liquid crystal
Authors: Dion J. L. , Jacob A. D.
Published: February 2003

The visible interaction of low-intensity ultrasonic waves with a nematic liquid crystal may be explained simply by the hypothesis of a torque tending to orient LC molecules perpendicular to the vibrations. It is shown how this torque can be related to anisotropic attenuation of ultrasound and minimization of propagation losses. First theoretical developments and optical measurements on a homotropic layer of MBBA are in good agreement and may predict a few simple general laws.
Fabrication of graded-index fibers without an index dip by chemical vapor deposition method
Authors: Akamatsu Takeshi , Okamura Koji , Ueda Yoichi
Published: February 2003

When optical fibers are prepared by the (CVD) technique, an index dip often appears at the core center. The index dip reduces the coupling efficiency to optical sources and also it reduces the transmission bandwidth. This index dip in the core with germania-doped silica could be eliminated successfully with a flow of the vapors of controlled proportion of GeCl4 and O2 during the collapse. The graded-index fibers without dip were prepared by this technique. The bandwidth was increased from 500 to 800 MHz : km and the coupling efficiency by 20% when the index profile was controlled and the index dip was eliminated.
Evolution of polarization along a single-mode fiber
Authors: Simon A. , Ulrich R.
Published: February 2003

The local parameters of linear and circular birefringence are nondestructively measured along a single-mode optical fiber by electro-optic and magneto-optic modulation of the polarization in the fiber. A complete mapping of the evolution of the state of polarization is obtained and is compared with a theoretical model.
A novel double-heterostructure p-n-junction laser
Authors: SpringThorpe A. J.
Published: February 2003

Oxide-stripe laser and Burrus LED technologies have been combined to enable DH GaAlAs p-n-junction lasers with emission perpendicular to the junction plane to be prepared.
Direct measurement of ultrasonic Stoneley waves
Authors: Claus Richard O. , Palmer C. Harvey
Published: February 2003

Stoneley waves have long been assumed to exist between rock strata deep within the earth’s crust. We report the first direct measurements of Stoneley waves, in this case generated at 8 MHz and propagated along nickel-Pyrex and other interfaces. The optically measured wavelengths agree with calculated values within 1%. The waves are not detected between unsuitable material pairs. Possible applications are suggested.
Transient capacitance measurements of hole emission from interface states in MOS structures
Authors: Schulz M. , Johnson N. M.
Published: February 2003

The energy spectrum of MOS interface states and the capture cross section for holes have been measured in p-type silicon by transient capacitance spectroscopy. In MOS capacitors with interface state densities of <1010 cm−2 eV−1 near midgap, the density decreases with energy towards the valence-band edge over the measurement range of 0.17 <E−Ev<0.6 eV. The capture cross section for holes is of the order of 5×10−13 cm2 and is independent of temperature and energy. It appears that the measured distribution consists of acceptor states that extend from the conduction band into the lower half of the silicon forbidden band. The absence of a detectable signal from interface states in a valence-band tail implies that the capacitance transient for hole emission is outside the measurement range. A sharply peaked signal observed for electron (minority carrier) capture at high temperatures indicates that these states are present, but have an extremely low capture cross section for holes, ⩽10−23 cm2.
Degradation of high-radiance Ga1−xAlxAs LED’s
Authors: Yamakoshi Shigenobu , Hasegawa Osamu , Hamaguchi Hisashi , Abe Masayuki , Yamaoka Toyoshi
Published: February 2003

The slow degradation of single-heterostructure Ga1−xAlxAs LED’s has been investigated. The samples which show the fast degradation are completely rejected by the selection of DLD-free LED’s. Selection procedures and the results of accelerated aging tests for over 10 000 h are presented. The activation energy of the slow degradation is found to be 0.57 eV. Extrapolated room-temperature half-life in excess of 5×106 h is estimated. The degradation coefficients are not affected significantly by the operating current density (3.5–10 kA/cm2).
Deuterium isotope enrichment in methane-hydrogen mixtures subjected to a low-temperature glow discharge
Authors: Manuccia T. J. , Geosling C. E.
Published: February 2003

Significant enrichment of deuterium has been demonstrated in flowing CH4-H2 mixtures subjected to a low-temperature glow discharge. In the best case, over 500% enrichment per stage was measured. A pronounced translational temperature effect was observed with the optimum enrichment occurring at Twall=−105 °C.
The use of nuclear reactions and SIMS for quantitative depth profiling of hydrogen in amorphous silicon
Authors: Clark G. J. , White C. W. , Allred D. D. , Appleton B. R. , Magee C. W. , Carlson D. E.
Published: February 2003

Depth profiles for hydrogen in amorphous silicon have been determined by the use of resonant nuclear reactions [1H(15N,αγ)12C and 1H(19F,αγ)16O] and by secondary ion mass spectroscopy (SIMS). Independent calibration procedures were used for the two techniques. Measurements were made on the same amorphous silicon film to provide a direct comparison of the two hydrogen analysis techniques. The hydrogen concentration in the bulk of the film was determined to be about 9 at.% H. The SIMS results agree with the resonant nuclear reaction results to within 10%, which demonstrates that quantitative hydrogen depth profiles can be obtained by SIMS analysis for materials such as amorphous silicon.
Infrared holography on commerical wax at 10.6 μm
Authors: Beaulieu R. , Lessard R. A. , Cormier M. , Blanchard M. , Rioux M.
Published: February 2003

Holograms have been recorded with far-infrared radiation (10.6 μm) on ’’Takiwax’’ films. The relief-phase holograms obtained due to the thermal process involved are reconstructed, in real time, with He-Ne laser light. Reconstruction from grating holograms in the infrared with 10.6-μm CO2 laser radiation is also possible: diffraction efficiencies of up to 15% have been measured for two-beam gratings.
Mercuric bromide photodissociation laser
Authors: Schimitschek E. J. , Celto J. E. , Trias J. A.
Published: February 2003

Laser action was achieved on the B 2Σ+→X 2Σ+ transition of the HgBr radical by photodissociating HgBr2 in the vapor phase. The pump radiation was the 193-nm output of an ArF excimer laser. The measured laser wavelengths range from 502 to 505 nm. In transverse excitation, the measured output energy of the HgBr laser was 0.25 mJ at a pump energy of 7 mJ.
Thin-film machining by laser-induced explosion
Authors: Zaleckas Vicent J. , Koo Jackson C.
Published: February 2003

This paper describes a process for the laser machining of thin metallic films on dielectric substrates. The observation of a distinct minimum in the machining threshold and the fact that no substrate damage occurs over a wide range of incident power are explained based on an explosive film-removal mechanism. Experimental results supporting the predictions are presented.
Electromechanical devices utilizing thin Si diaphragms
Authors: Guckel H. , Larsen S. , Lagally M. G. , Moore G. , Miller J. B. , Wiley J. D.
Published: February 2003

Heavy boron diffusion followed by selective etching has been used to produce uniform edge-supported Si diaphragms with thickness in the 1–3-μ range and areas up to 5 cm2. These diaphragms have numerous applications in the fabrication of rugged reliable electromechanical devices which are compatible with IC technology. In this paper we describe the performance of an electrically tunable resonant cavity which operates in the 10–12-kHz range with Q as high as 23 000. Devices based on this cavity structure include pressure transducers, microphones, speakers, tunable filters, and oscillators.
Parallel transmission of a one-dimensional light distribution by a single optical fiber
Authors: Levy U. , Friesem A. A.
Published: February 2003

A technique, based on the preservation of the axial angle, for transmitting one-dimensional light distribution through a single multimode step-index optical fiber is described. Extension to transmission of two-dimensional pictures is demonstrated.
dc plasma anodization of GaAs
Authors: Chesler L. A. , Robinson G. Y.
Published: February 2003

Oxide films up to 2500 Å thick have been grown by anodization of GaAs in the negative glow region of a dc oxygen discharge. Using Auger analysis, as-grown samples were found to contain excess Ga in the bulk of the film and excess As in a wide oxide-GaAs interface region. Preliminary measurements indicate that plasma anodic films grown on both p- and n-type GaAs exhibit electrical properties similar to films formed by liquid anodization.
Calculations of ion-ion recombination rates at high pressures
Authors: Wadehra J. M. , Bardsley J. N.
Published: February 2003

The classical theory of ion-ion recombination in gases of high density is extended to allow for arbitrary ratios of the masses of the three species involved. Calculations are performed for the recombination of Ar+, Ar+2, Kr+, and Kr+2 ions with F− and of Hg+ and Ar+ with Cl− in an argon gas. The effective two-body rates peak between 2×10−6 and 3×10−6 cm3 sec−1 at pressures above 1 atm.
Refractive-index-adjustable SiO2-Ta2O5 films for integrated optical circuits
Authors: Terui Hiroshi , Kobayashi Morio
Published: February 2003

This report is about the preparation and the optical transmission loss of rf-sputtered SiO2-Ta2O5 films that are suitable for use as transmission media in integrated optical circuits. It is shown that the films, which can be produced with a refractive-index range from 1.46 to 2.08 at 6328 Å wavelength by suitably selecting the ratio of the target constituents, exhibit a low optical transmission loss of less than 0.8 dB/cm for the TE0 mode.
Electron-beam-controlled discharge XeCl excimer laser
Authors: Levatter Jeffrey I. , Morris James H. , Lin Shao-Chi
Published: February 2003

A large-volume (6-liter) electron-beam-controlled discharge of about 1 μsec duration in a Xe/Ar mixture with HCl as the chlorine donor has been utilized to achieve efficient XeCl laser generation at 3080 Å. At a fixed gas pressure and e-beam current, the laser output is found to increase rapidly with the initial sustainer field strength up to the spontaneous breakdown limit. Near such a limit, a factor-of-25 enhancement of the XeCl laser output energy over that due to e-beam pumping alone has been observed at 1 atm total pressure. The specific output pulse energy density and laser efficiency based on total energy deposition, of 0.5 J/liter atm and 0.7%, respectively, are beginning to approach the best values reported in the literature for the XeF and KrF lasers.
Photosensitivity in optical fiber waveguides: Application to reflection filter fabrication
Authors: Hill K. O. , Fujii Y. , Johnson D. C. , Kawasaki B. S.
Published: February 2003

The observation of photosensitivity in Ge-doped core optical fibers is reported. The photosensitivity is manifested by light-induced refractive-index changes in the core of the waveguide. Narrowband reflectors in a guide structure have been fabricated using this photosensitivity and the resulting DFB reflectors employed as laser mirrors in a cw gas laser in the visible.
Determination of boron and phosphorus concentration in silicon by photoluminescence analysis
Authors: Tajima Michio
Published: February 2003

A novel method to obtain boron and phosphorus concentration in silicon crystals by photoluminescent (PL) analysis at liquid-helium temperature is reported. The intensity ratio between intrinsic and extrinsic components in the PL spectra reflects the impurity concentration. The tentative calibration curves for boron and phosphorus for our method are obtained by comparison with the results of the resistivity measurement. The detection limit of this method is estimated to be as low as 1×1011 cm−3 for boron and 5×1011 cm−3 for phosphorus. The degree of compensation can be estimated also. The PL method makes it possible to determine nondestructively the concentration of small amount of impurities in a small region of a specimen.
Pulse-width dependence on intracavity bandwidth in synchronously mode-locked cw dye lasers
Authors: Ausschnitt C. P. , Jain R. K.
Published: February 2003

We present a model of the synchronously mode-locked cw dye laser which predicts a square root dependence of dye pulse width on pump pulse width and intracavity bandwidth (ωc). Experiments performed on the Rhodamine 6G laser confirm the ω−1/2c dependence. For a pump pulse width of 100 ps, subpicosecond dye pulses are obtained for intracavity bandwidths greater than 150 Å, and the minimum pulse width is shown to be limited by the bandwidth of the dye to ∼0.5 ps.
Liquid-phase epitaxial growth of lattice-matched InGaAsP on (100)-InP for the 1.15–1.31-μm spectral region
Authors: Feng M. , Windhorn T. H. , Tashima M. M. , Stillman G. E.
Published: February 2003

The distribution coefficients for the growth of lattice-matched InGaAsP on (100) -InP substrates in the 1.15–1.31-μm spectral range have been determined. These results have been used in the growth of heterojunction photodiodes with quantum efficiencies ⩾48% at 1.27 μm.
Low-resistivity ZnCdS films for use as windows in heterojunction solar cells
Authors: Romeo N. , Sberveglieri G. , Tarricone L.
Published: February 2003

Low-resistivity ZnxCd1−xS films have been obtained by a multisource evaporation method. The films have been doped with In during the deposition. The resistivity of such films varies from 2×10−3 Ω cm for x=0 up to 2 Ω cm for x=0.3 and rises up to 1012 Ω cm for x=1. For energies lower than the energy gap, the transparency of these films, when corrected for the reflection loss, can reach a value of almost 100%. In the range of an x variation between 0 and 0.4 these films, because of their low resistivity and their high transparency, can be used as windows in heterojunction solar cells.
cw optical wave-front conjugation by saturated absorption in atomic sodium vapor
Authors: Liao P. F. , Bloom D. M. , Economou N. P.
Published: February 2003

Reconstructed images have been obtained by direct wave-front conjugation in atomic sodium vapor using a cw tunable dye laser. With a pump power of only 15 mW a conversion efficiency of 0.2% has been observed.
Deep-level spectroscopy in high-resistivity materials
Authors: Hurtes Ch. , Boulou M. , Mitonneau A. , Bois D.
Published: February 2003

A simple method to characterize deep levels in high-resistivity materials is described. Excess carriers are optically injected by pulsed light. The detrapping of these carriers leads to a transient current collected between two contacts. The signal is analyzed as in DLTS, i.e., deep level spectra are recorded during temperature cycles. Some examples of the use of this method are given.
Unidirectional contraction in boron-implanted laser-annealed silicon
Authors: Larson B. C. , White C. W. , Appleton B. R.
Published: February 2003

The lattice contraction in boron-implanted laser-annealed silicon has been studied by x-ray Bragg reflection profiles and ion channeling. The contraction was shown to be one dimensional, along the surface normal, for strains as large as 1.3%.
Surface electromagnetic wave launching at the edge of a metal film
Authors: Chabal Y. J. , Sievers A. J.
Published: February 2003

Propagating ir surface electromagnetic waves have been launched on and off the edges of a metallic film evaporated on the base of an NaCl prism. The coupler does not make use of an air gap or a grating.
Subpicosecond pulses from a tunable cw mode-locked dye laser
Authors: Heritage J. P. , Jain R. K.
Published: February 2003

Tunable subpicosecond pulses (pulse width =0.8 psec) have been obtained from a cw mode-locked Rhodamine B dye laser. Mode locking is achieved by synchronous pumping of the Rh-B dye with a cw train of pulses which are obtained from a synchronously mode-locked Rhodamine 6G dye laser.
On the cooling rates of large-diameter silicon crystals
Authors: Capper P. , Wilkes J. G.
Published: February 2003

A theoretical study has been carried out on the cooling rates of silicon crystals, with diameters between 50 and 100 mm, from 650 °C to room temperature under natural and forced convection conditions. Experimental results are described for a 75-mm-diam crystal, again in both natural and forced convection conditions, and are seen to agree well with the theoretical predictions. The significance of the results is discussed in terms of actual changes in donor concentration of a Czochralski-grown crystal, after ’’annealing’’ at 650 °C, and it is concluded that ’’annealing’’ of ingots may not be sufficient for close-tolerance materials and reheating of slices may be necessary.
Formation of metallic LiH
Authors: Vaišnys J. Rimas , Žmuidzinas Jonas S.
Published: February 2003

It is calculated that a metallic form of LiH will occur at a pressure of 1.1 Mbar, with a molar volume of 5.0 cm3 mole−1.
Observation of the time-reversed replica of a monochromatic optical wave
Authors: Jensen S. M. , Hellwarth R. W.
Published: February 2003

We have generated, essentially instantaneously, a time-reversed (TR) replica (phase conjugate) of a monochromatic optical wave (at 6943 Å). Replication occurred through an interaction with a standing pump wave (at the same frequency) mediated by the instantaneous nonlinear refractive index of liquid CS2. The power in the TR replica could be made up to half that in the beam being replicated before other nonlinear effects intervened.
A general relation between resistance fluctuations from enthalpy fluctuations and resistance response to current changes
Authors: Weissman Michael B.
Published: February 2003

The spectral shape and magnitude of spontaneous resistance fluctuations due to enthalpy fluctuations are shown to be determined by the resistance response to current impulses for a broad class of resistors, including any resistor containing only one type of conducting material, regardless of the resistor geometry. Implications for the design and interpretation of experiments are discussed.
Light-sensitive Rayleigh-wave generation by surface piezoelectricity
Authors: Fossheim K. , Bjerkan L.
Published: February 2003

A simple method is described for generation and detection of surface waves in nonpiezoelectric dielectrics due to creation of a space-charge region and a polarized surface layer under the interdigital electrodes. By direct evaporation of electrodes onto the surface of nonpiezoelectric materials, and without use of dc bias, Rayleigh waves with a signal-to-noise ratio as high as 60 dB have been generated. We have demonstrated the method on cubic KTaO3 and cubic BaTiO3. Additional application of dc bias further enhances the signal which is retained even after removal of the bias. High sensitivity to band-gap illumination is observed, allowing a direct determination of the band gap.
Surface acoustic wave properties of fresnoite, Ba2Si2TiO8
Authors: Melngailis John , Vetelino J. F. , Jhunjhunwala A. , Reed T. B. , Fahey R. E. , Stern E.
Published: February 2003

Surface acoustic wave properties of fresnoite have been calculated from bulk material parameters and have been measured along several orientations on samples cut from Czochralski-grown crystals. Favorable properties are measured for the z-cut x-propagating wave: the coupling coefficient k2 is 0.016±0.003, the velocity is 2678 m/sec, and the temperature coefficient of delay is 51×10−6/ °C. These values, as well as those measured for the much lower coupling x-z and x-y surface waves, are in agreement with calculations. The calculations also predict that, for surface waves propagating in the x direction on a surface whose normal is at 45° to z and y axes, the coupling coefficient is 10% higher than calculated for the above z-x case.
Sustained discharge excitation of HgCl and HgBr B2Σ+1/2→X2Σ+1/2 lasers
Authors: Whitney W. T.
Published: February 2003

This letter reports e-beam-sustained discharge excitation of HgCl and HgBr lasers operating on the green and blue-green B2Σ+1/2→X2Σ+1/2 bands in 2-atm mixtures of Ar/Hg/Cl2 and Ar/Hg/BrCCl3. The excitation channel appears to be through the reaction of Hg(3P) metastable atoms with the halogen-containing species.
Optical waveguides in LiNbO3 formed by ion implantation of helium
Authors: Destefanis G. L. , Townsend P. D. , Gailliard J. P.
Published: February 2003

The paper reports the formation of optical waveguides in LiNbO3 by the implantation of helium ions. The ion beam damage defines the low-index regions which surround the waveguide. The computed index profile and the observed modes are in agreement. Changes in n0 of up to 7% are recorded as a saturation index change.
Room-temperature laser operation of quantum-well Ga(1−x)AlxAs-GaAs laser diodes grown by metalorganic chemical vapor deposition
Authors: Dupuis R. D. , Dapkus P. D. , Holonyak Nick , Rezek E. A. , Chin R.
Published: February 2003

The achievement of room-temperature (300 °K) operation of Ga(1−x)AlxAs-GaAs double-heterostructure lasers with active layers of quantum-well dimensions ∼200 Å thick is reported. These devices are grown by metalorganic chemical vapor deposition and exhibit pronounced effects in the spectral and lasing characteristics that are related to the small active region thickness and are the first such effects observed for DH lasers in the GaAlAs-GaAs system.
Quantitative flow visualization in sodium vapor seeded hypersonic helium
Authors: Miles R. B. , Udd E. , Zimmermann M.
Published: February 2003

Sodium vapor seeded into a hypersonic helium flow through an orifice on a model is used as a tracer to determine velocity profiles. A narrow-linewidth tunable dye laser is scanned across the Doppler-shifted absorption line of the sodium and the resonant fluorescence is observed. Curves showing the velocity-shifted pressure- and temperature-broadened absorption lines at several points in the flow are presented. Fluorescence is strong enough to use this technique for quantitative flow visualization: at each laser frequency, a specific velocity component is highlighted and easily observed by eye.
Ionic recombination of rare-gas atomic ions X+ with F− in a dense-gas X
Authors: Flannery M. R. , Yang T. P.
Published: February 2003

Rates for the recombination processes X++F−+X→XF*+X, (X≡He, Ne, Ar, Kr, Xe) at 300 K are calculated for pressures of the background gas X in the range ∼0.1–50 atm. Rates as high as (2–7) ×10−6 cm3 sec−1 are obtained for pressures 1–5 atm of Xe→He, and in general decrease with increasing ionic mass, except at low gas densities.
Two-dimensional simulation of the hydromagnetic Rayleigh-Taylor instability in an imploding foil plasma
Authors: Roderick N. F. , Hussey T. W. , Faehl R. J. , Boyd R. W.
Published: February 2003

Two-dimensional (r-z) magnetohydrodynamic simulations of the electromagnetic implosion of metallic foil plasmas show, for certain initial configurations, a tendency to develop large-amplitude perturbations characteristic of the hydromagnetic Rayleigh-Taylor instability. These perturbations develop at the plasma magnetic field interface for plasma configurations where the density gradient scale length, the characteristic dimension for the instability, is short. The effects on the plasma dynamics of the implosion will be discussed for several initial foil configurations. In general, the growth rates and linear mode structure are found to be influenced by the plasma shell thickness and density gradient scale length, in agreement with theory. The most destructive modes are found to be those with wavelengths of the order of the plasma shell thickness.
Oriented crystal growth on amorphous substrates using artificial surface-relief gratings
Authors: Smith Henry I. , Flanders D. C.
Published: February 2003

Oriented crystal growth on an amorphous substrate has been achieved using an artificially created surface-relief grating. Crystallites of KCl grown from a water solution onto a 320-nm spatial-period square-wave grating in SiO2 nucleated preferentially at vertical steps and grew with 〈100〉 directions parallel to the grating axis. It is proposed that artificially created surface microstructures may provide a new means of manipulating the growth and orientation of crystalline overlayers.
A superconducting transistor
Authors: Gray K. E.
Published: February 2003

A three-film superconducting tunneling device, analogous to a semiconductor transistor is presented, including a theoretical description and experimental results showing a current gain of 4. Much larger current gains are shown to be feasible. Such a development is particularly interesting because of its novelty and the striking analogies with the semiconductor junction transistor.
BOXCARS: Crossed-beam phase-matched CARS generation in gases
Authors: Eckbreth Alan C.
Published: February 2003

CARS generation from N2 has been demonstrated using a crossed-triple-beam phase-matching technique. This approach can provide greater and unambiguous spatial resolution for diagnostic purposes in contrast to the conventionally employed collinear phase-matching schemes. The technique has been dubbed BOXCARS based upon the shape of the phase-matching diagram.
A high-resolution electron microscopy study of the Si-SiO2 interface
Authors: Krivanek O. L. , Sheng T. T. , Tsui D. C.
Published: February 2003

We have studied the Si-SiO2 interface of a Si-MOSFET (metal-oxide-semiconductor field-effect transistor) on a (911) surface by high-resolution electron microscopy. The interface was viewed edge-on parallel to [011̄] and the Si crystal lattice was directly resolved. The image shows the interface to be smooth to within 4 Å and contains a possible indication of a transition layer (∼10 Å) of nonstoichiometric oxides.
An electronic transition chemical laser
Authors: McDermott W. E. , Pchelkin N. R. , Benard D. J. , Bousek R. R.
Published: February 2003

cw laser action was achieved on the 2P1/2→2P3/2 transition of the iodine atom by energy transfer from the 1Δ metastable state of O2. The excited oxygen was generated chemically by flowing chlorine gas through a basic solution of 90% H2O2. The effluent from the oxygen generator was mixed with molecular iodine at the entrance of a longitudinal flow laser cavity where the I2 was dissociated by a small amount of O2(1Σ) that was present in the flow due to energy pooling processes. The measured output power was greater than 4 mW.
Fluorescence yields of metal halide vapors excited by photodissociation
Authors: Maya Jakob
Published: February 2003

We have measured the absolute quantum efficiency (photon ratio) of atomic and/or molecular fluorescence owing to excitation by photodissociation at 205 nm (FWHM=15 nm) in a number of metal halide vapors. The measurements were done at pressures of about 0.1 Torr. The results are TlI=0.42, InI=0.20, HgI2=0.09, HgBr2=0.26, ZnI2=0.14, and CdI2=0.09. We believe these to be the first measurements of fluorescence yields in the metal halide vapors.
The growth of GaxIn1−xAs on (100) InP by liquid-phase epitaxy
Authors: Pearsall T. P. , Bisaro R. , Ansel R. , Merenda P.
Published: February 2003

We have grown a series of films of the ternary alloy GaxIn1−xAs on (100) InP near the lattice-matched composition Ga0.47In0.53As. The results show clearly that the distribution coefficient of gallium is about 10% larger for growth on the (100) face than on the (111B) face of InP. Thus we show that the solid composition obtained in liquid-phase epitaxy under near-equilibrium growth conditions is strongly affected by factors other than the liquid composition and temperature.
Diffusion in a Pd-Cu-Si metallic glass
Authors: Chen H. S. , Kimerling L. C. , Poate J. M. , Brown W. L.
Published: February 2003

The diffusivities (D) of a Pd77.5Cu6Si16.5 glass above the glass transition agree within a factor of 3 with diffusivities (Dη) evaluated from viscosity data using the Stokes-Einstein relationship. Below the glass transition, however, the measured D is critically related to the state of structure and can be many orders of magnitude higher than Dη. The time constant for structural relaxation is suggested to be at least three orders of magnitude longer than that for diffusion processes.
Ge-Sn barrier Josephson tunnel junctions
Authors: Hu E. L. , Jackel L. D. , Strnad A. R. , Epworth R. W. , Lucey R. F. , Zogg C. A. , Gornik E.
Published: February 2003

A new form of superconducting Josephson tunnel junction has been developed in which superconducting electrons tunnel through thick (∼600 Å) barriers formed by evaporated Ge-Sn mixtures. By varying barrier composition and thickness a wide range of junction I-V characteristics can be obtained. For thick barriers, or barriers with low Sn content, high tunneling resistances and no supercurrent result. Barriers of intermediate thickness or with moderate Sn content yield junctions with electrical properties very similar to conventional hysteretic oxide-barrier junctions. Thin, or high Sn content barriers, give junctions with nonhysteretic I-V characteristics similar to those expected for an ideal superconducting microbridge. The nonhysteretic junctions could be used in nonlatching Josephson logic circuits. In addition, the nonhysteretic junctions show excellent microwave response, and may be useful for millimeter-wave mixing and detection.
Blistering effects in argon-bombarded silicon
Authors: Wittmaack K. , Wach W.
Published: February 2003

Blistering of silicon due to argon bombardment has been observed at implantation energies above about 100 keV. Above about 200 keV rupture of blisters becomes the predominant surface damage phenomenon. Blistering effects are most obvious upon first appearance. Further bombardment causes the occurrence of new generations of blisters accompanied by oscillations in argon content of the silicon backing. The effects are interpreted in terms of argon agglomeration, build-up of critical argon pressures, argon release from near-surface regions, and sputtering.
Periodic regrowth phenomena produced by laser annealing of ion-implanted silicon
Authors: Leamy H. J. , Rozgonyi G. A. , Sheng T. T. , Celler G. K.
Published: February 2003

We have discovered that interference effects extant during pulsed laser irradiation annealing of ion-implanted silicon produce periodic property variations in the annealed material that mimic the interference pattern. These are manifest at near-annealing threshold power densities as surface ripple and at higher power densities may be revealed by etching. The surface ripple observed at low power densities is correlated with the occurrence of polycrystalline silicon regions in the annealed material. Our observations suggest that surface melting and epitaxial regrowth are responsible for the annealing effect.
Metastable silicon–transition-metal films as temperature-independent resistors
Authors: Collver M. M.
Published: February 2003

The transition from semiconductor to metallic type behavior of the conductivity in crystalline metastable silicon–transition-metal films has been observed at transition-metal concentrations less than 15 at.%. The stability of these films makes them useful as temperature-independent resistors.
Studies of ion-beam-generation efficiency with reflex tetrodes
Authors: Mahaffey R. A. , Pasour J. A. , Golden J. , Kapetanakos C. A.
Published: February 2003

The unidirectionality of the ion current ina reflex tetrode has a result the efficient generation of pulsed ion beams. In this paper, experimental results are reported on the dependence of the ion-generation efficiency, in a reflex tetrode, upon the applied voltage, total current, anode-anode and anode-cathode separations, applied magnetic field.
A simple approach to estimate the size of small surface cracks with the use of acoustic surface waves
Authors: Tittmann B. R. , Cohen-Ténoudji F. , de Billy M. , Jungman A. , Quentin G.
Published: February 2003

The scattered radiation patterns of surface cracks irradiated by acoustic surface waves are interpreted to provide estimates of crack size. The technique is demonstrated for cracks as small as 100 μm in radius with an accuracy of about 10%.The key features are the positions and spacings of nulls in the angular dependence of the backward scattered surface-wave intensity. A simple model based on optical diffraction theory is presented and demonstrated on cracks (made with the identation technique) in commercial hot-pressed silicon nitride studied at 100 MHz and on cracklike flaws in commercial aluminum studied at 2–10 MHz.
Room-temperature continuous operation of photopumped MO-CVD AlxGa1−xAs-GaAs-AlxGa1−xAs quantum-well lasers
Authors: Holonyak N. , Kolbas R. M. , Dupuis R. D. , Dapkus P. D.
Published: February 2003

Room-temperature continuous operation (cw, 300 °K) of photopumped AlxGa1−xAs-GaAs-AlxGa1−xAs quantum-well heterostructure lasers embedded in Cu under diamond windows is demonstrated. The quantum-well heterostructures are grown by metalorganic chemical vapor deposition (MO-CVD) and possess undoped (nd−na≲1015/cm3) or compensated (nZn∼1019/cm3, nSe∼8×1018/cm3) GaAs active layers of thickness Lz∼200 Å.
Work function and Auger measurements of the initial oxidation of hydrogenated amorphous Si and of single-crystal Si
Authors: Goldstein Bernard , Szostak Daniel J.
Published: February 2003

We have monitored the change in work function during the initial oxidation of discharge-produced amorphous Si(H) and correlated this change with the amount of adsorbed oxygen as measured by Auger spectroscopy. With exposure to oxygen, the work function first increases (explained in terms of a dipole layer on the surface) and then decreases (explained in terms of penetration of oxygen below the surface). The explanation appears to be confirmed by similar measurements on the three primary crystallographic faces of single-crystal Si. Initial sticking coefficient and dipole strength of oxygen adsorbed on amorphous Si are given.
An ac method of Seebeck coefficient measurement by the use of lasers
Authors: Kawai M. , Tahira K. , Kitagawa K. , Miyakawa T.
Published: February 2003

The frequency dependence of thermoelectric power and the resistivity change induced by the infrared radiation from a chopped laser beam is used to estimate the Seebeck coefficient of semiconductor samples. The use of data on temperature dependence of resistivity eliminates the need for the measurement of rapidly varying temperature and its gradient within the sample. The method is tested for p-Ge samples and good agreement is obtained with the results of usual dc measurement.
Role of stresses in annealing of ion-implantation damage in Si
Authors: Seshan K. , EerNisse E. P.
Published: February 2003

Recent results showing a crystallographic orientation dependence of growth kinetics, secondary defects, and stress relief in annealing of ion-implanted Si are shown to be self-consistent if interpreted in terms of the influence of stresses upon annealing processes. The stress influence proposed is microplastic shear which is induced in [112] directions on (111) planes inclined to the implant surface by the biaxial stress created in the implant region by ion-implantation damage. The shear stresses are shown to be dependent on crystallographic orientation in a manner consistent with the model.
Polycrystalline fiber optical waveguides for infrared transmission
Authors: Pinnow D. A. , Gentile A. L. , Standlee A. G. , Timper A. J. , Hobrock L. M.
Published: February 2003

A new type of fiber optical waveguide utilizing TlBr and KRS-5 has been prepared; its infrared transparency extends to wavelengths well beyond those transmitted by known glassy materials.
Focusing and phase conjugation of photon echoes in Na vapor
Authors: Griffen N. C. , Heer C. V.
Published: February 2003

The focusing and phase conjugation of photon echoes was observed in Na vapor. If the radius of curvature of the first pulse was R1 and the second pulse R2, the radius of curvature of the echo was given by 1/RE=2/R2−1/R1 and the echo center of curvature or focus followed from the phase φE(r) =2φ2(r)−φ1(r) in the Na cell.
Singe-mode cw operation of ’’double-dovetail’’ constricted DH (AlGa)As diode lasers
Authors: Botez Dan
Published: February 2003

Constricted double-heterojunction (CDH) lasers have been prepared in a double-dovetail channel structure, which consistently provides cw fundamental-mode operation. Oscillation in both single lateral and single longitudinal modes (spectral halfwidth <0.09 Å) is obtained at drive currents 50–100% above threshold and to cw power levels as high as 12 mW. ’’Kinkless’’ power-current curves at 20 and 70°C have been obtained from all lasers prepared to date to power levels close to that at which degradation occurs (∼30 mW cw at 20 °C for a 3–4-μm-wide lasing region). Threshold currents of 55–75 mA and external differential quantum efficiencies (one facet) of 15–17% are obtained from 120–150-μm-long diodes with a reflector on one facet. Threshold current ratios as low as 1.26 have been measured between 20 and 70 °C.
Interferometric waveguide modulator with polarization-independent operation
Authors: Burns W. K. , Giallorenzi T. G. , Moeller R. P. , West E. J.
Published: February 2003

A Mach-Zehnder interferometric waveguide modulator is demonstrated which simultaneously modulates both TE and TM modes. Two sets of electrodes are utilized to provide approximate independent control of vertical and horizontal field components across the channel waveguides. In Z-X–cut LiNbO3 this is shown to provide two polarization-independent points of operation. With Ti-diffused waveguides operated at 0.633 μm we obtained 90–95% modulation with applied voltages of 1.3 and 44 V and also with −8 and −36 V. Electrode design and alignment are shown to be important factors in device operation.
Laser-induced reactions of platinum and other metal films with silicon
Authors: Poate J. M. , Leamy H. J. , Sheng T. T. , Celler G. K.
Published: February 2003

We have reacted thin Pt, Pd, and Ni films with single-crystal Si using Q-switched Nd : YAG laser pulses of 100-nsec duration in the power range 18–50 MW cm−2. The layers are laterally very uniform in thickness but are not single phase. Average composition of the reaction product layer can be changed over a wide range by varying film thickness and laser power. The microstructure of the reacted layers indicates that reaction occurs via surface melting, mixing, and rapid resolidification.
Spatially resolved photoluminescence characterization and optically induced degradation of In1−xGaxAsyP1−y DH laser material
Authors: Johnston W. D. , Epps G. Y. , Nahory R. E. , Pollack M. A.
Published: February 2003

We have observed growth- and processing-related defects and optically induced degradation in In1−xGaxAsyP1−y double-heterostructure material intended for 1.2–1.3-μm laser diodes. Threshold for the degradation observed decreases with increasing layer thickness, suggesting a relation to strain arising from compositional variation during growth.
Ambipolar diffusion measurements in semiconductors using nonlinear transient gratings
Authors: Jaraŝiūnas K. , Gerritsen H. J.
Published: February 2003

The theory of self-diffraction of light by transient free-carrier gratings in semiconductors has been expanded to the case in which nonlinear absorption of light creates the grating. Its application to the experiments performed allowed determination of the free-carrier ambipolar diffusion coefficients in CdS, CdSe, and ZnSe crystals, and the mechanism of free-carrier recombination and carrier lifetime in CdS at low temperatures.
Depth profiling of sodium in SiO2 films by secondary ion mass spectrometry
Authors: Magee Charles W. , Harrington William L.
Published: February 2003

A focused beam of electrons in coincidence with a high current density Ar+ sputtering beam and SIMS detection has been used to perform accurate depth profiling analyses of sodium in SiO2 films. Conditions for exact charge compensation are described, and analyses of a 150-keV sodium implant in a 0.73-μm film of SiO2 are presented. Without charge neutralization, 98% of the implanted sodium moved to the SiO2/Si interface during SIMS analysis, whereas optimum charge compensation resulted in a basically unaltered implant profile with only 0.06% sodium at the interface.
Orientation of crystalline dipoles in poly(vinylidene fluoride) films under electric field
Authors: Naegele D. , Yoon D. Y.
Published: February 2003

Orientation of molecular dipoles in poly(vinylidene fluoride) (PVF2) films under electric field has been measured by ir spectroscopy using ir transparent indium-tin-oxide electrodes. Significant changes in ir transmission with electric field have been observed at 512 and 446 cm−1, which demonstrate that crystalline dipoles in β-phase PVF2 orient along the electric field. As the field is cycled between positive and negative values, the dipole orientation exhibits a hysteresislike behavior, demonstrating that the polarization of β-phase PVF2 and its switching result directly from the orientation of crystalline dipoles. Time response of dipole orientation shows that the total orientation consists of an instantaneous part and a slowly developing part. Only the latter seems to contribute to the remnant polarization and its switching.
Thermal-pulse technique for determining charge distributions: Effect of measurement accuracy
Authors: von Seggern Heinz
Published: February 2003

We examine how the thermal-pulse technique for determining spatial charge distribution in charged polymer foils is affected by inaccuracies of the measuring process. A theoretical model is developed for thermal equalization processes which is in agreement with the measured temperature transients. Using this model, we show by computer simulation that even for a measurement inaccuracy of less than 1% the obtainable information consists of only the first moment of the charge distribution and the first few Fourier coefficients.
Long-duration high-efficiency operation of a continuously pulsed copper laser utilizing copper bromide as a lasant
Authors: Chen Che Jen , Bhanji Alaudin M. , Russell Gary R.
Published: February 2003

A copper laser utilizing copper bromide as a lasant and neon as the buffer gas has been operated at an average laser power of between 16 and 19.5 W for a period of 68 h. Lasing was attained at a pulsing rate of 16.7 kHz in a quartz discharge tube 2.5 cm in diameter with an electrode separation of 200 cm. The laser energy/pulse and peak power/pulse corresponding to an average power of 19.5 W are 1.2 mJ and 30 kW, respectively. The ratio of laser power at 510.6 and 578.2 nm varied from 3.9 to 1.1 corresponding to a total average laser power of 4 and 18 W, respectively. The highest wall plug and capacitor efficiency measured during 68 h of operation was 0.7 and 1.1%, respectively.
Crystallization kinetics of Fe-B amorphous alloys
Authors: Luborsky F. E. , Liebermann H. H.
Published: February 2003

Amorphous Fe-B ribbons with 72-88 a/o Fe were prepared by melt-spinning. The inception of crystallization and the growth of crystals was determined by differential scanning calorimetry. The activation energy, ΔE, and the pre-exponential constant, A, for both the inception of crystallization and the peak in the crystallization exotherm are independent of composition from 72-82 a/o Fe. ΔE and A steadily decline as the Fe content is increased from 82 to 88 a/o Fe. The concurrence of the ΔE and A values for the inception of crystallization and for the peak in the crystallization exotherm suggests that the same diffusion mechanism is controlling the kinetics in both periods. This compositional dependence of constants in the Arrhenius relation is attributed to decreased filling of holes by B in the Bernal-like structure as the Fe content increases.
Heteroepitaxy of deposited amorphous layer by pulsed electron-beam irradiation
Authors: Lau S. S. , Tseng W. F. , Nicolet M-A. , Mayer J. W. , Minnucci J. A. , Kirkpatrick A. R.
Published: February 2003

We demonstrate that a single short pulse of electron irradiation of appropriate energy is capable of recrystallizing epitaxially an amorphous Ge layer deposited on either 〈100〉 or 〈111〉 Si single-crystal substrate. The primary defects observed in the 〈100〉 case were dislocations, whereas stacking faults were observed in 〈111〉 samples.