bluuebunny/crossref_metadata_2025 huggingface dataset:
C−V analysis of a partially depleted semiconducting channel
Authors: Lehovec Kurt
Published: February 2003

C−V analysis applied to a depletion layer bordering a semiconducting channel does not provide the true impurity distribution if the space−charge region penetrates to another depletion layer at the other side of the channel, i.e., if the channel is partially depleted. Cases in point are an epitaxial semiconducting channel on a semi−insulating chromium−doped gallium arsenide substrate; an n−channel on a p−substrate; and a heterojunction of a semiconducting epitaxial layer on an insulating substrate with interface states causing depletion.
Contributions of multiphoton absorption to laser−induced intrinsic damage in NaCl
Authors: Bräunlich P. , Schmid A. , Kelly Paul
Published: February 2003

Intrinsic damage of NaCl upon exposure to intense laser pulses is discussed in terms of electron kinetic processes. Avalanche ionization is confirmed to be the dominant mechanism at the ruby frequency. However, compared to pure avalanche breakdown, both five−photon absorption and, to a lesser extent, the presence of F centers reduce the damage threshold by providing a large concentration of free carriers at the onset of avalanche ionization. Three−photon absorption contributes extensively to damage at the doubled ruby frequency. The dependence of the damage threshold on the laser pulse length is calculated and it is shown that its measurement can provide information on the role of multiphoton absorption in the damage process. At a given wavelength multiphoton contributions become increasingly more important as the laser pulse length decreases.
Anomalous dispersion effects on pulse propagation in high−pressure CO2 amplifiers
Authors: Schappert G. T. , Herbst M. J.
Published: February 2003

We have measured the time delay of a P (20) short pulse propagating through a high−pressure CO2 amplifier under small−signal−gain conditions. The reduced velocity agrees with the group velocity, which is about 0.92c. The effect is proportional to the small signal gain divided by the linewidth.
Enhancement of pyroelectricity in a vinylidene fluoride−tetrafluoroethylene copolymer
Authors: Baise A. I. , Lee H. , Oh B. , Salomon R. E. , Labes M. M.
Published: February 2003

Pyroelectric coefficients of a copolymer of vinylidene fluoride (95%) and tetrafluoroethylene (5%) have been measured, and were found to be significantly higher than those obtained for the poly(vinylidene fluoride) homopolymer. The effect of poling time and the nature of the (first cycle) thermally stimulated currents are also compared.
Backscatter measurements from laser-produced plasmas at 10.6 μm
Authors: Mitchell K. B. , Stratton T. F. , Weiss P. B.
Published: February 2003

The fraction of light backscattered from plasmas produced by 10.6-μm laser light focused on polyethylene slab targets is ∼5% of the incident for intensities between 1013 and 1015 W/cm2. Time-integrated measurements of the spectrum of backscattered light near 10.6 μm are presented.
High-pressure infrared Ar-Xe laser system: Ionizer-sustainer mode of excitation
Authors: Newman L. A. , DeTemple T. A.
Published: February 2003

Laser action on neutral Xe transitions has been achieved at 1-atm pressure in Ar-Xe and He-Xe mixtures excited in an ionizer-sustainer mode of discharge. A number of near-infrared lines oscillated in both mixtures with the strongest at 1.73 μm in Ar-Xe. Over-all conversion efficiencies of 0.2% in He-Xe and 1% in Ar-Xe were obtained with resulting output powers of 100–200 kW. These represent an order-of-magnitude increase in power, energy per pulse, and efficiency over previously reported observations on conventional transverse discharge lasers.
Comparison of interface-state generation by 25-keV electron beam irradiation in p-type and n-type MOS capacitors
Authors: Ma T. P. , Scoggan G. , Leone R.
Published: February 2003

The interface state induced by 25-keV electron beam irradiation in MOS capacitors having p- and n-type substrates with several different doping concentrations have been studied. For radiation dosage on or above the order of 1×10−5 C/cm2, all of the radiation-induced interface-state distributions tend to have a similar shape which is asymmetrical about the midgap, independent of the type and concentration of the silicon dopants, and independent of the initial interface-state distributions. The states in the upper half of the silicon band gap are acceptor type which peak around 0.2 eV from the midgap, whereas the states in the lower half of the band gap are donor type with a lower density. For radiation dosage below 1×10−7 C/cm2 the postradiation interface states are proportional to their initial values. An explanation based on the broken bond model is presented to account for the observations.
Low-power cw generation of coherent anti-Stokes Raman radiation in CH4 gas
Authors: Barrett J. J. , Begley R. F.
Published: February 2003

Coherent continuous wave anti-Stokes Raman scattering has been observed using a fixed-frequency pump beam (at the argon laser wavelength 514.53 nm) and a tunable-frequency Stokes beam (provided by a dye laser at 605.41 nm) focused in a cell containing 1 atm of CH4 gas. This four-frequency mixing experiment utilized the ν1 symmetric vibrational mode in CH4 at 2916.7 cm−1, resulting in a coherent anti-Stokes signal at 447.37 nm. The power measured in the 514.53-nm pump beam was 0.46 W and the effective power in the Stokes beam was calculated to be about 36 mW. The calculated coherent anti-Stokes power of 2.18×10−13 W agrees very well with the experimentally observed anti-Stokes power.
High-resolution direct-display x-ray topography
Authors: Hartmann W. , Markewitz G. , Rettenmaier U. , Queisser H. J.
Published: February 2003

A new system for the direct video display of x-ray diffraction topographs is described. The pattern is converted to an optical signal by a fine-grain fluorescent screen, which is viewed by a video camera through a magnifying optical system. We have achieved a resolution of about 10 μm, suitable for detailed direct observations of individual dislocations in materials such as silicon. The system combines efficient usage of source intensity, large field of vision, and circumvention of an electronic suppression of Kα2 images.
Frequency-controlled cw tunable GaAs laser
Authors: Picqué J.-L. , Roizen S.
Published: February 2003

A cw single-mode tunable GaAs diode laser has been locked to an external passive cavity by making use of the dependence of the output frequency on the injection current. The resulting long-term stability of the laser optical frequency was checked by reference to a microwave frequency standard, through the light-shift effect in a cesium vapor. The laser frequency was found to track the drift of the cavity bandpass with residual variations less than 300 kHz rms. Servo-controlled frequency scanning was achieved over 5 GHz.
Ferromagnetism in metallic FexTaS2 (x≈0.28)
Authors: Eibschütz M. , DiSalvo F. J. , Hull G. W. , Mahajan S.
Published: February 2003

Single crystals of FexTaS2 (x≈0.28) are metallic, ferromagnetic (Tc=73±5 °K), and have a large coercive force of 55 kOe at 4.2 °K. Mössbauer measurements show the iron to be high-spin Fe2+, with a distribution of hyperfine fields at low temperatures. Electron microscopic observations, together with these results, suggest the presence of iron clusters.
Theory of elasto-optic coefficients in polycrystalline materials
Authors: Flannery M. , Marburger J.
Published: February 2003

We estimate strain-optic coefficients for polycrystalline laser window materials, and show that they deviate appreciably from the single-crystal values. p11−p12 may change sign and grow in magnitude relative to the single-crystal value.
Optical characterization of a native oxide anodically grown on gallium antimonide
Authors: Aspnes D. E. , Schwartz B. , Studna A. A. , Derick L.
Published: February 2003

The dielectric function and refractive index of an anodically grown mixed oxide on GaSb have been measured ellipsometrically from 1.5 to 6.0 eV. The absorption edge was determined to occur at 4.2 eV, with a weak tail extending to 3.7 eV.
Amorphous silicon solar cell
Authors: Carlson D. E. , Wronski C. R.
Published: February 2003

Thin film solar cells, ∼1 μm thick, have been fabricated from amorphous silicon deposited from a glow discharge in silane. The cells were made in a p-i-n structure by using doping gases in the discharge. The best power conversion efficiency to date is 2.4% in AM-1 sunlight. The maximum efficiency of thin-film amorphous silicon solar cells is estimated to be ∼14–15%.
Continuously tunable multiatmosphere N2O and CS2 lasers
Authors: O’Neill F. , Whitney W. T.
Published: February 2003

We describe the operating characteristics of pulsed multiatmosphere electron-beam-controlled He:CO:N2O and He:CO:CS2 lasers. Continuous interferometric tuning of these lasers has been achieved giving a tunable linewidth of <0.1 cm−1 for a laser pulse energy of 115 mJ from N2O and 45 mJ from CS2.
Operation of ITO/Si heterojunction solar cells
Authors: Mizrah Tiberiu , Adler David
Published: February 2003

We have fabricated solar cells consisting of transparent conducting films of indium-tin oxide (ITO) rf sputtered onto wafers of single-crystalline Si. A model quantitatively explaining the experimental data for this MOS-type solar cell is presented.
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u investigation of the mobility of small gold clusters on cleaved MgO surfaces
Authors: Metois J. J. , Heinemann K. , Poppa H.
Published: February 2003

The mobility of small clusters of gold (≃10Å in diameter) on electron-beam-cleaved MgO surfaces was studied by in situ transmission electron microscopy under controlled vacuum (10−7 Pa range) and temperature conditions. During the first 10 min following a deposition at room temperature, over 10% of the crystallites moved over short distances (≃20Å) discontinuously, with a velocity greater than 150 Å/sec. 80% of the mobility events were characterized by the avoidance of proximity of other crystallites, and this was tentatively explained as the result of repulsive elastic forces between the interacting crystallites.
New CO2 laser bands in the 9–11-μm wavelength region
Authors: Reid J. , Siemsen K.
Published: February 2003

Thirty-six new lines in the 9–11-μm wavelength region have been observed in continuous emission from a CO2 laser. These lines are identified as rotation-vibration transitions in the (00°2-[10°1, 02°1]I) and (00°2-[10°1, 02°1]II) bands. Several hundred milliwatts of power have been obtained on most of these transitions.
High-efficiency blazed grating couplers
Authors: Aoyagi Takashi , Aoyagi Yoshinobu , Namba Susumu
Published: February 2003

High-efficiency blazed grating couplers have been successfully realized by using an ion etching technique. We observed that a guided wave was radiated as the leaky wave which appears selectively either above or below the grating depending on the direction of the propagation of the guided wave. The coupling efficiency from the guided wave into one of the leaky waves was about 97% at the blaze angle of 30°.
Resonance-enhanced infrared four-wave mixing by infrared-active molecules
Authors: Pellin Michael J. , Yardley James T.
Published: February 2003

We suggest that high-efficiency frequency upconversion and downconversion can be achieved by four-wave mixing in media containing infrared-active molecules. The high-efficiency results from the relatively large vibrational matrix elements and small energy denominators. Numerical calculations are presented for generation of radiation at 2ω1+ω2 in HCl where 2ω1 is tuned to an electric-dipole-forbidden vibration-rotation transition. We also present some general considerations for four-wave mixing in molecular media.
Anisotropy of thermionic electron emission values for LaB6 single-crystal emitter cathodes
Authors: Schmidt P. H. , Joy D. C. , Longinotti L. D. , Leamy H. J. , Ferris S. D. , Fisk Z.
Published: February 2003

Measurement of thermionic electron emission values for pointed LaB6 single-crystal emitter cathodes has shown that 〈110〉 axial orientations yield emission values ten times higher than 〈100〉 orientations at 1545 °K. Minimum values were obtained for the 〈510〉 directions. These findings seem encouraging in achieving perhaps two orders of magnitude higher emission fluxes as compared to tungsten emitters.
High-sensitivity read-write volume holographic storage in Bi12SiO20 and Bi12GeO20 crystals
Authors: Huignard J. P. , Micheron F.
Published: February 2003

Bi12SiO20 and Bi12GeO20 present the best known photorefractive sensitivity for read-write volume holographic storage (S−1≃300 μJ/cm2) combined with high-quality image reconstruction. Recording processes by photocarrier diffusion (no applied field) and by photocarrier drift are identified. The high photosensitivity is attributed to photocarrier displacements comparable to or larger than fringe spacings. Saturation diffraction efficiency at light power densities larger than 600 μW/cm2 at λ=514.5 nm occurs from complete photocarrier trap filling.
Schottky-barrier characteristics of metal–amorphous-silicon diodes
Authors: Wronski C. R. , Carlson D. E. , Daniel R. E.
Published: February 2003

Metal–amorphous-silicon Schottky barriers, similar to those used in thin-film amorphous-silicon solar cells, exhibit nearly ideal diode behavior in the dark. The current-voltage characteristics have been studied in the range from 270 to 370 °K and are found to be in agreement with the diffusion theory of metal-semiconductor rectification. Barrier heights, which were measured by two different methods, depend on the metal work function, and barriers as high as ∼1.1 eV are obtained with Pt films.
Recombination lasing in a magnetoplasmadynamic arcjet
Authors: Campbell E. M. , Jahn R. G. , von Jaskowsky W. F. , Clark K. E.
Published: February 2003

The plasmadynamic recombination laser concept is verified experimentally in a high-power quasisteady MPD arcjet operating at 4 kA and 12 g/sec of argon. Measurements of the spatial variation of electron temperature electron density, and population densities in the arc exhaust flow confirm that inverted populations of the 4p to 4s ArII transitions are established by collisional-radiative recombination of the ArIII ion. Using an optical cavity aligned transversely to the flow, recombination lasing of four such transitions, 5145, 4880, 4764, and 4727 Å, is observed spectrophotographically and photoelectrically over the entire 1-msec discharge.
A new semiconductor superlattice
Authors: Sai-Halasz G. A. , Tsu R. , Esaki L.
Published: February 2003

We treat theoretically, through the use of Bloch functions, a new semiconductor superlattice where the interaction of the conduction band in one host material with the valence band of the other host material plays an important role. The result indicates that this superlattice offers new intriguing features, realizable with the In1−xGaxAs-GaSb1−y Asy system. In addition, the tunneling probability is calculated across a barrier involving this system.
Vibration-induced modulation of fiberguide transmission
Authors: Nelson D. F. , Kleinman D. A. , Wecht K. W.
Published: February 2003

Linear intensity modulation of several percent in fiberguide transmission caused by flexural vibrations has been observed in bent fiberguides and attributed to modulated bending loss. Measurements of bending loss are presented which support this interpretation.
Preparation and characteristics of CuGaSe2/CdS solar cells
Authors: Romeo N. , Sberveglieri G. , Tarricone L. , Paorici C.
Published: February 2003

p-CuGaSe2/n-CdS heterojunctions have been prepared by depositing CdS films on p-type CuGaSe2 single crystals whose initial resistivity was 10−2 Ω cm and changed to 1 Ω cm after the CdS film deposition. The CdS films, which were grown by a multisources method, exhibit a room-temperature resistivity of 0.1 Ω cm. The absolute quantum efficiency of these devices as photovoltaic detectors reaches the value of 80% at a wavelength of 5800 Å. As solar cells, these heterojunctions at 25 °C display a solar power conversion efficiency of 5% when they are exposed to the solar light whose intensity is 71 mW/cm2. When the heterojunctions are directly polarized, they emit light in a broad band which is centered at ∼7700 Å. An external electroluminescent emission efficiency of about 0.05% has been measured at liquid-nitrogen temperature.
Enhancement of H+ fraction in hydrogen ion sources by means of predissociation method
Authors: Kim Jinchoon , Davis R. C.
Published: February 2003

The H+ fraction of a hydrogen beam from a duoPIGatron ion source has been enhanced by a predissociation method, in which the hydrogen gas is predissociated in a hot tungsten oven prior to the arc discharge, while the recombination rate is minimized by hot walls inside the arc chamber. Preliminary results indicate the method can result in a substantial increase in the H+ fraction.
Microsecond-pulse insulation and intense ion beam generation in a magnetically insulated vacuum diode
Authors: Luckhardt S. C. , Fleischmann H. H.
Published: February 2003

The insulation and ion generation characteristics of coaxial magnetically insulated diodes were tested using microsecond voltage pulses from a Marx generator with magnetic fields ranging up to 20 kG, voltages of 150–300 kV, and gap widths of 0.3–0.9 cm. Voltage standoff was observed for up to 4 μsec when using graphite or metallic electrodes. With plasma-producing nylon filament anodes, high-energy ion beam pulse lengths of up to 2 μsec and total charge generation densities of up to 7.5 μA sec/cm2 were obtained.
Photoacoustic determination of absolute optical absorption coefficient
Authors: Wetsel Grover C. , McDonald F. Alan
Published: February 2003

We propose and demonstrate that the photoacoustic effect can be used for absolute determination of the optical absorption coefficient. The photoacoustic signal is measured as a function of chopping frequency and compared to the theory of the photoacoustic effect. The essential agreement of theory and experiment over a restricted frequency makes possible the determination of the optical absorption coefficient (to within 10% in a test case). Observation of a characteristic leveling off of the photoacoustic signal at low frequencies for several materials is also reported.
Optical bistability and differential gain between 85 and 296 °K in a Fabry-Perot containing ruby
Authors: Venkatesan T. N. C. , McCall S. L.
Published: February 2003

Bistability, differential gain, discriminator, clipper, and limier actions were observed using a plano-concave Fabry-Perot cavity containing ruby. Input powers were approximately 20 mW from a cw ruby laser. Operation wa anticipated near 77 °K where the R1 transition was nearly resonant with the laser. However, the device functioned at room temperature. The refractive index of ruby depends on the fractional ground-state population. Driving the R lines leads to a nonlinear refractive index due to dispersive contributions from nonresonant pump and charge-transfer bands, which explains the room-temperature operation.
Enhancement of light emission from metal-insulator-metal tunnel junctions
Authors: McCarthy S. L. , Lambe John
Published: February 2003

Light emission from metal-insulator-metal tunnel junctions is enhanced using two schemes for improving photon-surface plasmo coupling. Results reported here establish that the light emission arises from radiative decay of junction surface plasmon modes excited by inelastic electron tunneling. The enhanced light-emitting tunnel junctions have an external quantum efficiency in the 10−5 range.
Influence of electrostatic fields on the properties of acoustically tuned optical filters
Authors: Wiczer James J. , Merkelo Henry
Published: February 2003

It is shown that an electrostatic field applied to the interaction medium of an acoustically tuned optical filter can shift the center wavelength of the optical passband, without significantly altering the optical bandwidth. For the crystallographic orientation of the LiNbO3 medium selected for this experiment, we verify a 2-Å shift in optical passband for each kV cm−1 of applied electrostatic field. This effect can be used to overcome limitations in the tuning range and/or electrical efficiency imposed by transducers in the operation of acoustically tuned optical filters. This phenomenon can be particularly useful in optical filters of small dimensions such as those found in integrated optical waveguide structures.
The implosion of cryogenic spherical shell targets
Authors: Henderson T. M. , Johnson R. R.
Published: February 2003

Spherical glass shells filled with deuterium-tritium gas have been used as cryogenic targets in neutron-producing experiments. Experiments were performed under cryogenic conditions to determine the state and form of the fuel at the time of arrival of the laser pulse in target interaction experiments. The results from neutron-producing experiments indicate that cryogenic targets implode significantly better than room-temperature targets under comparable experimental conditions and that the neutron production for cryogenic targets is significantly greater than for equivalent targets at room temperature.
Tunnel injection into the confined-particle states of an In1−xGaxP1−zAsz well in InP
Authors: Rezek E. A. , Holonyak N. , Vojak B. A. , Shichijo H.
Published: February 2003

Tunnel injection is demonstrated into the confined-particle states of an In1−xGaxP1−zAsz potential well, located on the p-type side of an InP p-n junction, leading to structure in the I-V, dI/dV, and d2I/dV2 characteristics and to step increases in the intensity of the recombination radiation at bias voltages V corresponding to the states of the well [eV∼Eg(InGaPAs) ∼hν<Eg(InP)].
Switching of GaAs IMPATT diode oscillator by optical illumination
Authors: Yen H. W. , Barnoski M. K. , Hunsperger R. G. , Melville R. T.
Published: February 2003

A study was made of the microwave oscillaton characteristics of GaAs IMPATT diodes under external optical illumination. It was found that depending on the diode’s bias condition, the frequency of oscillation and the intensity of illumination, the IMPATT microwave output power can be either enhanced or reduced.
Ink jet printing nozzle arrays etched in silicon
Authors: Bassous E. , Taub H. H. , Kuhn L.
Published: February 2003

Ink jet printing nozzle arrays in the form of truncated pyramidal holes anisotropically etched into a silicon substrate have been fabricated. Eight-nozzle arrays dixplay excellent performance characteristics with regard to uniformity of direction (<± 1mra), velocity (<± 10 cm/sec) at 1000–3000 cm/sec), and drop formation.
Current and C-V instabilities in SiO2 at high fields
Authors: Solomon P. M. , Aitken J. M.
Published: February 2003

Results have been obtained concerning the interrelation of current and C-V instabilities in MOS capacitors subjected to negative gate high-field pulsing. Rising current transients and negative C-V shifts both show the formation of positive charge in the oxide. However, this charge appears to be situated close to the electrodes rather than in the bulk of the oxide and the temperature dependence of the rate of charge accumulation near the electrodes is different for the aluminum and silicon electrodes. These results indicate that the current instabilities and C-V shifts appear to result from independent mechanisms.
A new inorganic electron resist of high contrast
Authors: Yoshikawa Akira , Ochi Osamu , Nagai Haruo , Mizushima Yoshihiko
Published: February 2003

A novel inorganic electron resist is proposed. It is shown that the electron irradiation on a stacked layer composed of a thin Ag film over a layer of Se-Ge chalcogenide amorphous glass enhances diffusion of Ag into Se-Ge glass, in the same manner as in the case of photodoping. The Ag-doped Se-Ge film becomes almost insoluble in alkaline solutions. A negative-type electron resist is realized by applying this effect. This inorganic electron resist is proved to exhibit an extremely high contrast (γ∼8). The sensitivity is 4×10−5 C/cm2 at 5 kV. It is confirmed that fine-pattern delineation of less than 0.3 μm linewidth is possible.
High-efficiency GaAlAs/GaAs heterostructure solar cells grown by metalorganic chemical vapor deposition
Authors: Dupuis R. D. , Dapkus P. D. , Yingling R. D. , Moudy L. A.
Published: February 2003

High-efficiency GaAlAs/GaAs heterostructure solar cells have been grown by metalorganic chemical vapor deposition (MO−CVD). Simulated air-mass-zero (AM0) short-circuit current densities of 24.5 mA/cm2, open-circuit voltages of 0.99 V, fill factors of 0.74, and efficiencies of 12.8% have been measured on devices without AR coatings (uncorrected for contact area). These cell structures employ a thin (∼520Å) GaAlAs : Zn window and a GaAs : Zn/GaAs : Se p-n junction grown entirely by the MO-CVD process.
Electron trap annealing in neutron transmutation doped silicon
Authors: Guldberg J.
Published: February 2003

Silicon doped by neutron transmutation to 1.2×1014 phosphorus atoms/cm3 was investigated with deep level transient spectroscopy using evaporated Au/n-Si diodes. Seven bulk electron traps were identified which appear after 30 min N2 anneal at temperatures between 425 and 725 °C. Five of these annealed in the manner characteristic of intrinsic defects studied by EPR and ir spectroscopy. Two may be related to residual oxygen and carbon complexes.
Photoelectrolysis of water at high current density: Use of ultraviolet laser excitation
Authors: Bocarsly Andrew B. , Bolts Jeffrey M. , Cummins Phillip G. , Wrighton Mark S.
Published: February 2003

The behavior of TiO2 and SrTiO3 photoanodes in cells for the photoelectrolysis of H2O has been investigated for high-intensity 351 364-nm excitation from an Ar ion laser. Intensities up to 380 W/cm2 have been used. For TiO2 a small amount of surface decomposition is found after irradiation at high intensity, whereas SrTiO3 undergoes no detectable changes. Current-voltage properties for both electrodes are essentially independent of light intensity up to the level of 380 W/cm2, and there is little if any change in quantum efficiency for electron flow. Photocurrent densities have been shown to exceed 5 A/cm2 for O2 evolution. Data show that the energy storage rate associated with the SrTiO3 photoelectrolysis can exceed 30 W/cm2; this represents the highest demonstrated rate of sustained optical to chemical energy conversion.
Alignment of liquid crystals using submicrometer periodicity gratings
Authors: Flanders D. C. , Shaver D. C. , Smith Henry I.
Published: February 2003

Spatial-period (320-nm) square-wave gratings fabricated on amorphous SiO2 substrates were used to produce uniform alignment of the director in nematic and smectic liquid-crystal layers. This demonstrates that molecular alignment can be achieved using surface structures fabricated by a planar process. A novel method of producing twisted-nematic liquid-crystal displays using surface gratings is described.
Anomalous migration of fluorine and electrical activation of boron in BF+2-implanted silicon
Authors: Tsai M. Y. , Streetman B. G. , Williams P. , Evans C. A.
Published: February 2003

Fluorine distribution profiles for silicon implanted with 150-keV 1×1015-cm−2 BF+2 at room temperature or at −110 °C have been measured by SIMS as a function of anneal temperature. Anomalous migration of fluorine during annealing is observed, and is explained in terms of recrystallization and impurity-gettering effects. Electrical carrier distribution profiles of room-temperature BF+2-implanted silicon, measured by differential Hall effect methods, demonstrate that boron is electrically activated by epitaxial recrystallization during 550 °C annealing. However, a damaged region near the crystalline-amorphous interface remains after recrystallization. This damaged layer is apparently responsible for the fluorine gettering.
Influence of electron-F2 collisions in rare gas–halide laser discharges
Authors: Nighan William L.
Published: February 2003

The influence of F2 vibrational excitation and direct dissociation by electron impact is examined for conditions typical of electron-beam-sustained KrF* lasers. For values of F2 fractional concentration greater than about 0.003 the results of this analysis indicate that the dissociation process e+F2→2F+e may significantly affect electron-metastable atom production efficiency, rare gas–halide excimer production efficiency, and gain.
GaAs-GaAlAs injection lasers on semi-insulating substrates using laterally diffused junctions
Authors: Lee C. P. , Margalit S. , Ury I. , Yariv A.
Published: February 2003

Low-threshold GaAs-GaAlAs lasers operating in a stable single mode have been fabricated using laterally diffused junctions. The lasers are fabricated on semi-insulating substrates and can be integrated with other components.
High-energy lasing of XeBr in an electric discharge
Authors: Sze Robert C. , Scott Peter B.
Published: February 2003

Using an electric discharge as the excitation source we have overcome the problem of Xe+2 absorption and have observed lasing at 282 nm in XeBr at the 60-mJ/pulse level. HBr is used as the halogen donor. Simultaneous laser oscillation at 291 nm in Br2 has also been observed. The present laser, however, has materials compatibility problems causing short static-fill lifetimes.
High-efficiency organic solar cells
Authors: Morel D. L. , Ghosh A. K. , Feng T. , Stogryn E. L. , Purwin P. E. , Shaw R. F. , Fishman C.
Published: February 2003

Organic solar cells based on merocyanine dyes have exhibited sunlight efficiencies in excess of 1% at ∼100 mW/cm2. This represents a significant improvement over previously reported values and brings such devices into the realm of practicality. The devices exhibit Voc’s as high as 1.2 V but are presently limited by field-dependent energy-dependent quantum efficiency. Though monochromatic efficiencies approaching 100% occur at high photon energies, these diminish to ∼35% at the main absorption peak in the visible. Based upon sunlight absorption, theoretical efficiencies for these devices appear high.
A SIMS analysis of deuterium diffusion in hydrogenated amorphous silicon
Authors: Carlson D. E. , Magee C. W.
Published: February 2003

Secondary ion mass spectroscopy (SIMS) has been used to measure the diffusion of deuterium in hydrogenated amorphous silicon. For a film deposited in a dc glow discharge in SiH4 at a substrate temperature of 315 °C, the diffusion data fits D (T) =1.17×10−2 exp(−1.53 eV/kT) cm2/s. This result implies that degradation of these films due to hydrogen out-diffusion at 100 °C will not be significant until after more than 104 years.
A mode-locked krypton ion laser with a 50-psec pulse width in the near uv
Authors: Steinmetz L. L. , Richardson J. H. , Wallin B. W.
Published: February 2003

The mode-locked near-uv output from a krypton ion laser is characterized and shown to produce near-transform-limited picosecond pulses. Applications to time-resolved fluoresence studies for chemical analysis are included.
Properties of laser-assisted doping in silicon
Authors: Affolter K. , Lüthy W. , von Allmen M.
Published: February 2003

Ohmic contacts and p-n junctions in p- and n-type silicon are generated with the aid of a laser. Doping was achieved by covering the surface of the silicon with a layer of dopant and melting locally with pulses from either a Nd : YAG or a CO2 laser. Typical residual resistances of the Ohmic contacts are of the order of 0.1–1 Ω cm2 and backward/forward resistance ratios of 104 were measured for the diodes. A model which takes account of segregation during the cooling process is discussed and shown to agree with the resulting distribution of dopant. Highly doped material was found in a surface layer of a thickness less than 0.5 μm. This thickness was independent of laser parameters.
Identification of oxide precipitates in annealed silicon crystals
Authors: Yang K. H. , Anderson R. , Kappert H. F.
Published: February 2003

We have investigated the electron loss spectra of precipitates formed in annealed silicon crystals. The precipitates, as well as residue of the precipitates in precipitation sites, uniquely give rise to an energy loss at 532 eV. The energy loss is due to the excitation of oxygen 1s electrons. The precipitates are therefore identified as silicon oxide.
Deep level associated with the slow degradation of GaAlAs DH laser diodes
Authors: Imai H. , Isozumi K. , Takusagawa M.
Published: February 2003

The deep-level emission at 1.0 eV is analyzed to be associated with the slow degradation of GaAlAs DH laser diodes. The intensity of this deep-level emission increases at the same rate as the increase in the threshold current during the slow degradation. The carrier lifetime does not change correspondingly to the increase in the threshold current. This deep level is considered to act as the photon-absorption center to cause the increase in the threshold current.
On the origin of periodic surface structure of laser-annealed semiconductors
Authors: Maracas G. N. , Harris G. L. , Lee C. A. , McFarlane R. A.
Published: February 2003

Observations on laser-irradiated GaAs are reported in which the phenomenon of induced surface periodicity is related to a nonlinear interaction between simultaneously oscillating axial modes of the laser. It is suggested that during surface melting and regrowth material is distributed along nodal lines of a standing acoustic wave pattern corresponding to the axial mode beat frequencies. The several patterns observed are not consistent with an interference effect at optical frequencies.
Redistribution of dopants in ion-implanted silicon by pulsed-laser annealing
Authors: White C. W. , Christie W. H. , Appleton B. R. , Wilson S. R. , Pronko P. P. , Magee C. W.
Published: February 2003

The redistribution of B, P, As, and Sb implanted into single-crystal silicon and subsequently laser annealed with a Q-switched ruby laser has been studied by secondary-ion mass spectrometry and ion backscattering. Substantial alteration of the as-implanted profiles occurs, which is pulse-energy-density dependent. The altered profiles are in good agreement with theoretical calculations to be presented in a subsequent paper which show that redistribution occurs as a result of diffusion in the molten state.
High critical currents in cold-powder-metallurgy-processed superconducting Cu-Nb-Sn composites
Authors: Flükiger R. , Foner S. , McNiff E. J. , Schwartz B. B.
Published: February 2003

Cold-powder-metallurgy-processed superconducting Cu-Nb-Sn (discontinuous) multifilamentary composites have been fabricated. Overall critical current Jc comparable to the best in situ and commercial multifilamentary Nb3Sn (scaled for the same Nb content) have been achieved. Values of Jc approximately 105 A/cm2 at 12 T, 5×104 A/cm2 at 14 T, and 2×103 A/cm2 at 18 T are observed for a material with Cu–40 wt.% Nb–20 wt.% Sn with respect to Cu. The physical characteristics of the starting materials and some advantages of the cold-powder-metallurgy process are discussed.
Laser calorimetric measurement of two-photon absorption
Authors: Bass Michael , Van Stryland Eric W. , Stewart A. F.
Published: February 2003

A laser calorimeter has been used to measure two-photon absorption in solids. This new technique provides greater sensitivity than is possible in nonlinear transmission measurements. The two-photon absorption coefficients of CdTe and CdSe at 1.06 μm using ∼16-nsec (FWHM) pulses are 0.13±0.04 and 0.050±0.014 cm/MW, respectively.
Ultra-high-gain laser-produced plasma laser in xenon using periodic pumping
Authors: Silfvast W. T. , Szeto L. H. , Wood II O. R.
Published: February 2003

Gain and power output from a transversely initiated CO2 laser-produced plasma laser in xenon were dramatically increased by introducing a periodic spatial variation in the 10.6-μm pumping radiation. Small-signal gains over 55%/cm of excitation length were measured.
A high-intensity scanning ion probe with submicrometer spot size
Authors: Seliger R. L. , Ward J. W. , Wang V. , Kubena R. L.
Published: February 2003

A liquid-metal gallium-ion source was imaged by unity-magnification single-gap accelerating lens with a postlens deflector to form a focused scanning probe. We report the dependence of the probe diameter and probe current on the lens acceptance half-angle. The results range between probe diameters of 1000 and 5000 Å at currents of 0.12–3.0 nA for half-angles of 1.2–6 mrad. The current density and brightness at the target for the 1000-Å-diam 57-kV probe were 1.5 A/cm2 and 3.3×106 A/cm2 sr, respectively. Astigmatic probes were also produced with dimensions smaller than 1000 Å.
Optoacoustic spectroscopy of liquids
Authors: Patel C. K. N. , Tam A. C.
Published: February 2003

We report a pulsed-dye-laser optoacoustic spectroscopy technique for sensitive measurements of weak absorption spectra of liquids. We have used this technique to measure the weak visible absorption band of benzene near 607 nm, due to the sixth harmonic of the C-H stretch. We obtain a signal-to-noise ratio exceeding 102 at the absorption peak. We estimate that with improved data handling, absorption features as small as 10−7 cm−1 should be detectable in liquids. This opens up new possibilities of trace-constituent detection and pollution monitoring in the liquid phase.
The Schottky-barrier height of Au on n-Ga1−xAlxAs as a function of AlAs content
Authors: Best J. S.
Published: February 2003

The Schottky-barrier height of Au on chemically etched n-Ga1−xAlxAs was measured as a function of x. As x increases, the barrier height rises to a value of about 1.2 eV at x≈0.45, then decreases to about 1.0 eV as x approaches 0.83. The barrier height deviates in a linear way from the value predicted by the ’’common-anion’’ rule as the AlAs mole fraction increases. This behavior is related to chemical reactivity of the Ga1−xAlxAs surface.
New infrared laser transitions in copper and silver hollow cathode discharge
Authors: Solanki R. , Latush E. L. , Fairbank W. M. , Collins G. J.
Published: February 2003

We have investigated infrared laser action in the 0.8–2-μ region originating from silver and copper atoms and ions excited in hollow cathode discharges. 34 new laser lines are reported. We also observed eight Ar I and one Xe I infrared laser lines, most of which have been observed previously. The discharge conditions for these transitions and their excitation mechanisms are discussed.
Low-temperature sintering of Pd/Ge films on GaAs
Authors: Grinolds H. R. , Robinson G. Y.
Published: February 2003

Rectifying metal-semiconductor contacts, produced by heat treatment of a thin evaporated layer of Pd/Ge on n-type GaAs, have been studied using Auger electron spectroscopy, x-ray diffraction, and current-voltage measurements. During sintering at temperatures below 350 °C, the Pd and Ge were found to interdiffuse on the nonreacting GaAs substrate to form PdGe and Pd2Ge. The formation of the germanide phases altered the Ge LMM Auger spectra and produced an increase in the Schottky barrier energy from 0.67 to 0.85 eV.
Multipass amplification and tuning of the blue-green XeF C→A laser
Authors: Fisher Charles H. , Center Robert E. , Mullaney George J. , McDaniel John P.
Published: February 2003

The output energy from a uv preionized discharge excited XeF C→A laser has been increased two orders of magnitude by injecting a dye laser pulse into the C→A oscillator cavity. Output energies greater than 4 mJ with a spectral bandwidth of approximately 3 nm have been measured. By tuning the injected dye laser pulse, the output from the C→A laser was tuned from 460 to 515 nm.
Photoacoustic characterization of cw argon-ion laser irradiation of Ge
Authors: McClelland J. F. , Kniseley R. N.
Published: February 2003

Photoacoustic detection has been used to characterize cw argon-ion laser irradiation of Ge. Laser-induced heating, damage, and melting are studied. The heating process is seen to be nonlinear with incident laser power until close to melting. Two laser-induced-damage time constants are obtained associated with thermal etching and oxidation. An incident power level of 2.24 W is estimated to initiate the melting of an undamaged Ge surface under the experimental conditions described.
Observations consistent with self-generated magnetic fields in CO2 laser-produced plasmas
Authors: Ebrahim N. A. , Richardson M. C. , Fedosejevs R. , Feldman U.
Published: February 2003

The spatial structure of extreme ultraviolet (XUV) line emission from plasmas produced by nanosecond CO2 laser pulses has been examined with a slitless normal-incidence vacuum-ultraviolet spectrograph in the 200–500-Å spectral region. The anomalous structural behavior of these spectra is consistent with the existence of self-generated magnetic fields. These fields could also explain the gross plasma structure observed through picosecond interferometry.
The characterization of highly-zinc-doped InP crystals
Authors: Mahajan S. , Bonner W. A. , Chin A. K. , Miller D. C.
Published: February 2003

Highly-zinc-doped InP crystals, grown along the 〈111〉 direction by the liquid-encapsulated Czochralski technique, have been characterized by x-ray topography, transmission cathodoluminescence, and transmission electron microscopy. It is observed that high zinc doping improves the perfection of crystals insofar as dislocations are concerned. However, not all of the dopant atoms are in solid solution, and it appears that some have clustered to form a high density (∼4×108 cm−2) of fine precipitates with an average size of ∼675 Å.
Redistribution of Cr during annealing of 80Se-implanted GaAs
Authors: Evans C. A. , Deline V. R. , Sigmon T. W. , Lidow A.
Published: February 2003

Cr in-depth distributions have been measured in Se-ion-implanted GaAs as a function of postimplant annealing using secondary-ion mass spectrometry (SIMS). Analysis shows that Cr redistributes into regions of residual damage following 800 °C annealing. As the damage anneals at higher temperatures, however, the Cr tends toward the GaAs surface. This phenomenon offers a plausible explanation of the discrepancies between the observed electrical and chemical distributions of ion-implanted Se.
Acoustic microscopy of interior planes
Authors: Jipson V. B.
Published: February 2003

It has been recently demonstrated that the acoustic microscope can be used to image planes relatively deep beneath the surface with a lateral resolution of approximately one acoustic wavelength. In order to minimize the aberration effects caused by refraction at the liquid-solid interface, liquid gallium is substituted for water as the coupling liquid, and mode conversion to shear waves within the solid is exploited. The imaging properties of this system are discussed from a geometrical viewpoint and some experimental results are presented.
Optical breakdown in NaCl and KCl from 0.53 to 10.6 μm
Authors: Soileau M. J. , Bass Michael
Published: February 2003

Directly comparable values of optical-breakdown fields in NaCl and KCl were obtained at several wavelengths by properly scaling the data according to measured dependencies on the laser-beam focal spot radius. The breakdown field for each material showed no significant variation with laser wavelength over the range 0.53–10.6 μm. However, the ratio of the fields for even the most breakdown-resistant NaCl and KCl samples changed with the spot radius in a manner suggesting that an extrinsic property dominates optical breakdown in these materials.
Six-beam irradiation and implosion of laser fusion targets: Laser focus dependence
Authors: Thorsos E. I. , Bristow T. C. , Delettrez J. A. , Soures J. M. , Rizzo J. E.
Published: February 2003

DT-filled 115-μm-diam. glass microballoons have been irradiated with the six-beam ZETA laser (Nd: phosphate glass) at 2 TW. The absorption uniformity and implosion symmetry have been studied with x-ray imaging for variations in the laser focal conditions. Symmetry, as indicated by the x-ray spatial emission of both the absorption region and the imploded core, has been found to be a strong function of illumination uniformity.
Annular discharge copper vapor laser
Authors: Kan T. , Ball D. , Schmitt E. , Hill J.
Published: February 2003

A large-volume high-power copper vapor laser excited by a longitudinal discharge in an annular volume has been demonstrated. The annular geometry provides a device configuration in which the laser prf, governed by a geometric diffusion length, can be made independent of the device volume. Laser powers of 35 W at a prf of 6 kHz has been obtained with an overall device efficiency of 0.44%.
Replication of 175-Å lines and spaces in polymethylmethacrylate using x-ray lithography
Authors: Flanders D. C.
Published: February 2003

A new technique for fabricating high contrast x-ray masks with simple patterns of lines and spaces less than 50 Å in width is described. The successful replication of 175-A lines and spaces in polymethylmethacrylate (PMMA) using the carbon K (45-Å) x-ray is reported. It was found that PMMA structures smaller than 150 Å in width lost their physical integrity and would not adhere to SiO2 substrates.
Filamentation instability of a self-focused relativistic electron beam
Authors: Segalov Z. , Goren Y. , Carmel Y. , Eylon S. , Ginzburg A.
Published: February 2003

Observations of filamentation instabilities in a self-focusing relativistic electron beam are presented. Such instabilities may enhance asymmetrical pellet heating in electron-pellet inertial fusion devices.
Surface hardness and abrasive wear resistance of nitrogen-implanted steels
Authors: Bolster R. N. , Singer I. L.
Published: February 2003

The hardness of nitrogen-implanted steel surfaces has been determined indirectly by a surface-sensitive abrasive wear technique using micrometer-size diamond particles. Wear rates were measured, as a function of depth, for implanted and unimplanted steel discs, and surface hardness was obtained from a verified relationship between wear rate and hardness. Tempered carbon steel implanted with nitrogen ions was significantly hardened to a depth commensurate with the implantation depth. Nitrogen-implanted 304 steel surfaces were softer than unimplanted ones, possibly due to interference with the work hardening which normally occurs during wearing. This softening effect persisted to depths several times the depth of implantaton. Composition-vs-depth profiles of implanted 304 steel obtained with Auger electron spectroscopy, indicated nitrogen migrated inward during wear.
Optical parameters for the MgO:Ni2+ laser system
Authors: Iverson M. V. , Windscheif J. C. , Sibley W. A.
Published: February 2003

The optical properties of the transitions of Ni2+ in MgO have been measured. The temperature dependence of these quantities is important for evaluation of the efficiency of MgO:Ni as a room-temperature tunable infrared laser. The measurements suggest that MgO:Ni is an excellent candidate for a tunable laser. A comparison of the optical properties with other materials and the use of the Struck and Fonger theory suggest that MgO:Co might also be an acceptable room-temperature infrared laser with greater tuning range.
The effect of ground state population on the XeF laser performance
Authors: Rokni M. , Jacob J. H. , Hsia J. C. , Trainor D. W.
Published: February 2003

In this letter we describe an investigation of the effect of the bound ground state of XeF on the laser performance. This was accomplished by observing the intensity of the sidelight fluorescence of the B (v′=0) →X (v″=3) as a function of laser flux at 353 nm. Our data indicate that the ground state dissociates more rapidly as the laser mixture temperature is increased from 300 to 500 °K. As a result of the faster dissociation rate at 500 °K, the XeF laser efficiency increases by ≈1.5 as the mixture temperature is increased from 300 to 500 °K.