bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression of oxidation-stacking-fault generation by preannealing in N2 atmosphere
Authors: Kishino Seigô , Isomae Seiichi , Tamura Masao , Maki Michiyoshi
Published: February 2003

Suppression of oxidation-stacking-fault (OSF) generation is studied by x-ray section topography, etching technique, and transmission electron microscopy (TEM). Microdefects (MD’s) are generated in bulk Si during N2 atmosphere annealing at about 1000–1100 °C, and their generation is confined to the inner part of the Si wafer. These MD’s grow rapidly during subsequent oxidation. The grown MD’s contribute to stacking faults (SF’s) in the inner part of bulk Si. On the contrary, surface OSF’s are not introduced by the subsequent oxidation because no MD’s are generated in the surface layer by the preannealing. The suppression effect of OSF generation by N2 atmosphere preannealing is demonstrated using several samples.
Microwave power gain utilizing superconducting resonant energy storage
Authors: Birx D. , Dick G. J. , Little W. A. , Mercereau J. E. , Scalapino D. J.
Published: February 2003

Energy stored in a superconducting resonator has been switched to an external load producing a pulse of microwave power. The peak power in the pulse was nine times that of the source feeding the cavity, and the pulse was observed to be phase locked to the source.
Conformal antireflective coatings on a textured tungsten surface
Authors: DiStefano T. H. , Pettit G. D. , Woodall J. M. , Cuomo J. J.
Published: February 2003

A conformal antireflective coating of WO3 on a textured tungsten surface is found to significantly increase the optical absorptance of the surface over a broad selected band of wavelengths. The coating enhances the selectivity of solar absorbing surfaces on dendritic tungsten and increases the solar absorptance of such surfaces. The average solar absorptance measured at air mass 2 was increased from 0.95 to 0.985 for large dendrite surfaces and from 0.76 to 0.90 for small dendrite surfaces. Emittance values for the anodized surfaces at 300 °C range from 0.18 for the small dendrites to 0.5 for the larger dendrites. The WO3 conformal coating, produced by anodization of the tungsten, forms an antireflective coating with a minimum at a wavelength between 0.43 and 0.8 μ for anodization voltages between 20 and 40 V, respectively. Total reflectances as low as 0.00025 have been measured.
Use of oxygen-doped AlxGa1−xAs for the insulating layer in MIS structures
Authors: Casey H. C. , Cho A. Y. , Nicollian E. H.
Published: February 2003

Metal-insulator-semiconductor capacitors were prepared by doping an Al0.5Ga0.5As layer with oxygen in order to demonstrate a lattice-matched single-crystal insulator-semiconductor heterojunction. Crystal growth was by molecular-beam epitaxy. Interface trap effects were not observed in capacitance-voltage measurements, while the current-voltage measurements show space-charge-limited currents for forward and reverse biases.
Stress-induced enhancement of T
c in bronze-processed V3Ge
Authors: Bussiere J. F. , Onishi T. , Welch D. O. , Suenaga M.
Published: February 2003

Compressive stresses arising from differential contraction of the bronze matrix were found to cause an increase in the critical temperature, Tc, of bronze-processed V3Ge. This unusual behavior for an A-15 compound is in qualitative agreement with Testardi’s theory, although the enhancement of Tc does not increase parabolically with strain and saturates at strains of ∼0.5%.
Specific heats of NdP5O14 and PrP5O14 near their ferroelastic phase transitions
Authors: Loiacono G. M. , Delfino M. , Smith W. A.
Published: February 2003

The specific heats of NdP5O14 and PrP5O14 were measured with a differential scanning calorimeter over the temperature range 385–440 °K. The ferroelastic phase transition was confirmed to be second order. The ferroelastic transition temperatures for NdP5O14 and PrP5O14 were 426.5 and 416.5 °K, respectively. A second thermal anomaly was observed in both materials approximately 20 °K below the ferroelastic transition.
Preliminary results on the conversion of laser energy into electricity
Authors: Thompson R. W. , Manista E. J. , Alger D. L.
Published: February 2003

A preliminary experiment was performed to investigate conversion of 10.6-μm laser energy to electrical energy via a laser-sustained argon plasma. Short-circuit currents of 0.7 A were measured between thoriated-tungsten emitter and collector electrodes immersed in the laser-sustained argon plasma. Open-circuit voltages of ∼1.5 V were inferred from the current-voltage load characteristics. The dominant mechanism of laser energy conversion is uncertain at this time. Much higher output powers appear possible.
Electron drift velocities in helium-fluorine gas mixtures
Authors: Nygaard Kaare J. , Fletcher John , Hunter Scott R. , Foltyn Stephen R.
Published: February 2003

Using a simple time-of-flight technique, we have measured the electron drift velocity in helium with 0.1–1% fluorine additive. Our results in a 0.1% mixture are in close agreement with data in pure helium. The measured drift velocity increases with increasing fluorine concentration.
Image phase compensation and real-time holography by four-wave mixing in optical fibers
Authors: Yariv Amnon , AuYeung John , Fekete Dan , Pepper David M.
Published: February 2003

It is proposed that real-time holography can be performed inside multimode fibers (or optical waveguides) using four-wave optical mixing. Of particular interest is the generation of complex-conjugate replicas of input fields for image transmission and compensation of propagation distortion. A theoretical analysis and a numerical estimate are presented.
Scaling of nonthermal ion energy in laser-generated plasma
Authors: Wägli P. , Donaldson T. P. , Lädrach P.
Published: February 2003

Plasma was generated by focusing a 1.06-μm 35-psec laser pulse obliquely onto a solid surface at the optimum resonance absorption angle. The scaling of nonthermal ion emission energy with laser intensity was determined. A computer model for resonance absorption showed nonthermal ion emission to be due to electron acceleration by a resonantly driven electrostatic field.
Dichroism measurements in photoacoustic spectroscopy
Authors: Fournier D. , Boccara A. C. , Badoz J.
Published: February 2003

Photoacoustic spectroscopy is used to obtain dichroism spectra of strongly absorbing samples. The effects, natural or magnetically induced, are recorded with a scale directly comparable to that of the absorption data. The validity of the experiments has been examined using conventional dichroism and absorption techniques on a thin slice of a NdMoO4 crystal.
Balanced bridge modulator switch using Ti-diffused LiNbO3 strip waveguides
Authors: Ramaswamy V. , Divino M. D. , Standley R. D.
Published: February 2003

An experimental integrated optical version of the Mach-Zehnder interferometer switch, analogous to the microwave balanced bridge, is reported. The bridge is formed by 3-μm-wide Ti-diffused strip waveguides in LiNbO3 and the switch utilizes electro-optical tuning to achieve 3-dB operation of the directional couplers. The switching voltage required to switch between the states, corresponding to a π phase shift in one arm, equals 14.8 V. The cross talk between channels that corresponds to the extinction ratio when operated as an on-off modulator is −21.6 dB.
Lifetime and quenching rate constants for Kr2F* and Kr2*
Authors: Quigley G. P. , Hughes W. M.
Published: February 2003

A broadband 2.5-ns-long argon excimer photolytic source was used to initiate the reaction sequence resulting in the formation of Kr2F*. The resulting fluorescence signal at 400 nm depended on the radiative and quenching processes of Kr2* as well as Kr2F*. The radiative lifetime of Kr2F* was found to be 181±12 ns. The rate constants for quenching by F2 and Kr are 4.3±0.4×10−10 and 6.9±0.7×10−15 cm3 s−1, respectively. The Kr2* coupled lu, Ou lifetime is 280±30 ns and the rate constant for quenching of Kr2* by F2 is 2.1±0.2×10−10 cm3 s−1.
A transversely rf-excited CO2 waveguide laser
Authors: Lachambre J.-L. , Macfarlane J. , Otis G. , Lavigne P.
Published: February 2003

An electrodeless CO2 waveguide laser with transverse rf pumping is described. In the rf cw mode, the laser emits up to 0.6 W at 100 Torr. In the rf pulse mode, atmospheric operation has been achieved with pulse duration of 20 μs and peak power of a few watts at a repetition rate of 300 Hz.
Dye laser pumped atomic iodine laser
Authors: Davis S. J.
Published: February 2003

Lasing has been demonstrated on the 2P1/2–2P3/2 transition in atomic iodine by optically pumping I2 vapor to dissociation with a flashlamp-pumped tunable dye laser. Lasing at 1.315 μ has been observed for pump wavelengths from 5010 to 4930 Å. The device holds promise as a rapidly pulsed gain diagnostic for existing or future iodine systems.
Cold working Nb3Al in the bcc structure and then converting to the A-15 structure
Authors: Webb G. W.
Published: February 2003

It is possible to quench gram quantities of stoichiometric Nb3Al in the ductile body-centered cubic structure which can be cold worked. Later annealing converts this material to the brittle superconducting A-15 structure.
Low-noise Josephson mixers at 115 GHz using recyclable point contacts
Authors: Taur Y. , Kerr A. R.
Published: February 2003

Thermally recyclable Nb point-contact Josephson junctions are investigated as low-noise mixers with an external local oscillator at 115 GHz. The best single sideband mixer noise temperature achieved is 140 (±20) K with a (SSB) conversion loss of 2.4 (±0.5) dB. Such rugged junctions are suitable for use in practical receivers and should give unprecedented sensitivity at the shorter millimeter wavelengths.
A new dielectric facet reflector for semiconductor lasers
Authors: Ettenberg Michael
Published: February 2003

Described in this letter is a new dielectric reflector designed for injection laser facets which consists of alternating quarter-wavelength layers of Al2O3 and Si. The reflectivity for six layers can be made ≳0.98 over a wavelength range from ∼0.7 to ≳2 μm. By choosing the appropriate number of quarter-wavelength layers and the final layer thickness the reflectivity can be varied between 0.01 and 0.98. Finally, both Si and Al2O3 are impervious to the chemical cleaning and wetting agents and solders used during the mounting of (AlGa)As cw injection lasers.
New quenching rates applicable to the KrF laser
Authors: Eden J. G. , Waynant R. W. , Searles S. K. , Burnham R.
Published: February 2003

Photolysis of KrF2 has been used to measure the rates of collisional quenching of KrF(B) excimers in two- and three-body collisions with Ar, Kr, and F2. In addition, the KrF(B→X) band radiative lifetime was determined to be 6.8±0.2 ns. The results are in good agreement with existing theory and demonstrate the importance of quenching to KrF laser performance.
EPR characterization of optical-quality AgGaS2 grown from the melt
Authors: von Bardeleben H. J. , Goltzené A. , Schwab C. , Feigelson R. S.
Published: February 2003

The EPR study of optical-quality AgGaS2 has proven the existence of the point defects Ni3+, Fen+, (n⩽2), a shallow donor (ED<0.11 eV), and one associated defect Fe3+-X, the charge states of which are all photosensitive. The effectiveness of the standard annealing procedures, employed to obtain crystals of low absorption in the 0.5–12-μm range, is associated with an oxidation of these transition-metal impurities.
Charge storage and photoconductivity of PbO powder layers
Authors: Ralph J. E. , Plummer M. J.
Published: February 2003

Photoconducting red lead monoxide powder layers treated with a rhodamine B dye and deposited on interdigital electrodes are shown to have novel properties. The equilibrium dark current measured at 10 V may be reduced by applying a voltage pulse. Typically 200-V pulses of 30 ms duration give a reduction of about 102 times. The recovery from this nonequilibrium condition in the dark and under 600- nm illumination at intensities between 5×10−9 and 5×10−7 W/cm2 is described. This behavior is discussed in terms of the depletion of grain-grain contacts by the surrounding charge stored in surface states associated with the adsorbed dye molecules.
The dynamic light scattering in the region of the ferroelectric phase transition in BaTiO3
Authors: Chanussot G. , Fridkin V. M.
Published: February 2003

The observation of a new effect, the photoinduced Rayleigh light scattering, (the PIRLS) was found in BaTiO3. This scattering has the two following features: it exists simultaneously with a bulk photovoltaic effect in BaTiO3 and it is an example of dynamic (but noncritical) scattering process. The main purpose of this letter is to describe the possible micromechanism responsible for the observed dynamic scattering close to the ferroelectric-paraelectric phase transition in BaTiO3.
Modulation of current in a thin film of lead tin selenide by bulk acoustic waves
Authors: Kowel S. T. , Kornreich P. G. , Szebenyi T. , Kaplan D.
Published: February 2003

We have measured a 0.1% modulation of electron current in a lead tin selenide film due to a bulk acoustic wave propagated in the barium fluoride substrate. This effect was observed as an ac component of the current at the acoustic frequency 0.6 MHz.
On an experimental and theoretical determination of tunnel current which sets off the avalanche in high-efficiency IMPATT diodes
Authors: Kennis P. , Chive M. , Constant E.
Published: February 2003

In Schottky-barrier (Pt–n GaAs) Read-type IMPATT diodes (Hi-Lo or Lo-Hi-Lo) it is now well known that the thermionic field-effect carrier injection (TFE) can decrease the diode microwave performances but also improve the noise properties under large signal levels. We present an experimental study to determine the TFE current which sets off the avalanche for voltage operation corresponding to oscillation or amplification conditions by measuring the back-bias effect in a pulse operation mode. Then using the tunnel current which has been checked by the present method, the variation of the optimum frequency operation for a high-low doping profile diode is calculated.
Existence of an isotope shift for the sulfur deep level in silicon
Authors: Myers D. R. , Phillips W. E.
Published: February 2003

The deep energy level of the isotope 34S in the upper half of the energy gap of silicon is examined by isothermal transient capacitance measurements on ion-implantation-predeposited diode structures. The resulting energy level at Ec−0.512 eV is found to be 0.014 eV closer to the conduction band edge than the corresponding deep level for the isotope 32S in similarly prepared samples. The existence of an isotope shift for the deep sulfur level is interpreted as implying vibronic coupling between the electronic states of the sulfur center and the silicon lattice.
Integration of an injection laser with a Gunn oscillator on a semi-insulating GaAs substrate
Authors: Lee C. P. , Margalit S. , Ury I. , Yariv A.
Published: February 2003

The integration of an injection semiconductor laser with an active electronic device (Gunn oscillator) in a single epitaxial crystal device is demonstrated.
Tunable high-efficiency microwave frequency shifting of infrared lasers
Authors: Carter Gary M.
Published: February 2003

By using the linear electro-optic effect in CdTe to mix a 10.6-μm laser output with a pulsed (1–4-μsec duration) microwave field produced by a magnetron, the laser’s output was shifted by 16 GHz with ≈ 27% conversion efficiency. By mechanically adjusting the microwave structure containing the CdTe and using a frequency-swept microwave source, the shift was demonstrated to be tunable from 13.9 to 17.0 GHz.
Photoluminescence recovery in rehydrogenated amorphous silicon
Authors: Pankove J. I.
Published: February 2003

The rehydrogenation of thermally dehydrogenated amorphous silicon restores the luminescence characteristics of a-Si : H.
A new method for determining thin-film refractive index and thickness using guided optical waves
Authors: Wei John S. , Westwood W. D.
Published: February 2003

We have developed a new method for determining thin-film refractive index and thickness. In this technique, a sharply converging laser beam is coupled into the film by a prism. Dark mode lines characteristic of the waveguide structure are observed in reflection independently of absorption or scattering loss in the film. A particularly promising application is the rapid sampling of dielectric films in semiconductor technology.
Acoustic microscopy at optical wavelengths
Authors: Jipson V. , Quate C. F.
Published: February 2003

Recent advances in the field of acoustic microscopy have allowed the instrument to be operated at wavelengths that correspond to the center of the optical band. Experimental results in the form of acoustic micrographs are presented and compared to their optical counterparts. It is apparent that the resolving power of the instrument is similar to that of the optical microscope. Also it is seen that the acoustic micrographs yield information on the subsurface region. This information is not available in the optical images.
Accurate measurement of small inductances or penetration depths in superconductors
Authors: Henkels W. H.
Published: February 2003

A technique for accurately measuring small superconductive inductances is presented. The inductance to be measured is inserted into a two-junction interferometer into which control current is directly injected. The method was used to measure the penetration depth of a Pb-In-Au alloy film and the effect of magnetic field fringing into a narrow superconductive stripline.
An acousto-optic real-time ’’two-crystal’’ correlator
Authors: Berg N. J. , Udelson B. J. , Lee J. N. , Katzen E.
Published: February 2003

A real-time correlator has been developed that utilizes successive acousto-optic interactions in two adjacent piezoelectric crystals (lithium niobate, LiNbO3, and bismuth germanium oxide, BGO) having surface-acoustic-wave (SAW) propagation velocities that differ by almost a factor of 2. Complex waveforms, such as FM chirps and Barker codes, have been correlated successfully. A large time-bandwidth product (∼3000) was obtained, and a 40-dB dynamic range was shown to be feasible. The use of this two-crystal device to obtain either pulse expansion or time inversion of a signal also was demonstrated.
Coherent radiation from an intense relativistic electron beam rotating in a background plasma
Authors: Granatstein V. , Roberson C. , Benford G. , Tzach D. , Robertson S.
Published: February 2003

Radiation at λ∼1 cm and megawatt power level is observed when a rotating, relativistic electron beam interacts with a background plasma. The emission spectrum is peaked at the 20th cyclotron harmonic, and the parametric dependence of the radiation is consistent with a model of interaction between single-particle cyclotron radiation and a beam-plasma streaming instability.
Effect of ionizing radiation on the optical attenuation in polymer-clad silica fiber-optic waveguides
Authors: Friebele E. J. , Jaeger R. E. , Sigel G. H. , Gingerich M. E.
Published: February 2003

The optical attenuation induced in polymer-clad silica fiber-optic waveguides by low-dose ionizing radiation (0.5–14 MeV) has been found to be much greater than expected on the basis of previous high-dose measurements. The radiation sensitivity is dependent upon the purity and OH content of the silica and upon the radiation history of the fibers, but it does not appear to depend upon the drawing conditions nor on the limited radiation-induced loss in the polymer cladding. The damage is greater at short times following the irradiation, and the decay kinetics of different synthetic silica fibers are qualitatively the same.
Optical surface waves in periodic layered media
Authors: Yeh Pochi , Yariv Amnon , Cho A. Y.
Published: February 2003

A generalized analysis of wave propagation in periodic layered media is applied to the special case of optical surface waves. These waves, confined to the interface between a periodic layered medium and a homogeneous medium, are formally analogous to electronic surface states in crystals. Single-mode surface-wave propagation along the surface of a GaAs-AlGaAs multilayer stack (grown by molecular-beam epitaxy) has been observed experimentally.
Formation and quenching processes in e–beam-pumped Kr/F2 mixtures
Authors: Jacob J. H. , Rokni M. , Mangano J. A. , Brochu R.
Published: February 2003

In this letter we report on measurements of the ion-ion recombination rate constant for the reaction Kr++F− +(M) →KrF*+(M) at pressures below 300 Torr. The rate constant is determined from the shape of the KrF* B 2Σ→X 2Σ fluorescence. The two-body quenching of KrF* by F2 has also been measured and the rate constant was found to be 7.8×10−10 cm3/sec. The two-body quenching of KrF* by Kr is negligible, while the three-body quenching by 2Kr was measured to be 6.7×10−31 cm6/sec. In evaluating the rate constants quoted above we have used the Dunning and Hay radiative lifetime for KrF* of 6.5 nsec.
Surface relief structures with linewidths below 2000 Å
Authors: Flanders D. C. , Smith Henry I. , Lehmann H. W. , Widmer R. , Shaver D. C.
Published: February 2003

We describe techniques for producing high-aspect-ratio vertical-walled relief gratings of 1600 Å linewidth with smooth line edges in SiO2 and Si substrates. Soft x-ray lithography (13.3–44.7 Å) is first used to expose such structures in PMMA. Liftoff of chromium and reactive sputter etching in CHF3 gas are then used to transfer the structure into the SiO2.
A laser-scanning apparatus for annealing of ion-implantation damage in semiconductors
Authors: Gat A. , Gibbons J. F.
Published: February 2003

The feasibility of annealing ion-implantation damage by means of a continuous high-power laser is demonstrated. An apparatus for the scanning of a semiconductor sample is described and a first-order set of optimum conditions for annealing ion-implanted Si is given. A preliminary comparison between laser and thermal annealing shows comparable results in terms of electrical activity of the annealed samples.
Fast diffusion of elevated-temperature ion-implanted Se in GaAs as measured by secondary ion mass spectrometry
Authors: Lidow A. , Gibbons J. F. , Deline V. R. , Evans C. A.
Published: February 2003

Depth profiles of Se-implanted GaAs samples have been measured as a function of substrate temperature during ion implanation using secondary ion mass spectrometry (SIMS). It has been found that Se diffuses anomalously fast during the implantation and that this diffusion is independent of implant time. Annealing of these implanted layers following the implantation, however, produces no additional diffusion even when annealed at 1000 °C for 15 min.
Brillouin scattering in a thin-film waveguide
Authors: Rowell N. , So V. C.-Y. , Stegeman G. I.
Published: February 2003

Brillouin scattering from thermal phonons in a thin-film integrated optics waveguide has been measured and interpreted to yield the elastic constants of the film.
p-n junction detector directly integrated with (Ga1−xAlx)As LOC-DBR laser
Authors: Shams Mohammad Kazem , Namizaki Hirafumi , Wang Shyh
Published: February 2003

Integration of a GaAs- (Ga1−xAlx)As LOC-DBR laser with a detector is demonstrated. For integrated laser-detector pairs in which the laser output is coupled to the detector via a 460-μm-long interconnecting waveguide, differential transfer efficiencies around 1% are measured. Threshold current densities as low as 6.4 kA/cm2 around room temperature are obtained.
Exciton transport in SiO2 as a possible cause of surface-state generation in MOS structures
Authors: Weinberg Z. A. , Rubloff G. W.
Published: February 2003

Positive charge and surface states are found to accumulate at the Si-SiO2 interface in MOS structures which are illuminated by vacuum ultraviolet photons (≳9 eV) with a negative bias applied to the metal electrode. A series of experiments seems to rule out the obvious explanations for this effect—photon and hot-electron processes. We suggest the possibility that excitons, generated by photon absorption in the SiO2, diffuse to the Si-SiO2 interface where they are separated into a free electron absorbed into the silicon substrate and a hole trapped at the interface.
High-intensity transmission characteristics of CH3-CHF2 and CHFCHF
Authors: Kung R. T. V. , Sirchis M.
Published: February 2003

The high-intensity transmission characteristics of CH3CHF2 and CHFCHF were investigated in the intensity range of 5×106 to 5×108 W/cm2 for various lines of the CO2 lasing branches. For similar gas pressures, the ratio of small to large intensity absorption coefficients is relatively constant at various CO2 lasing lines. The ratio of ∼6 measured for CH3CHF2 at 10.6 μm renders this molecule a good candidate for CO2 amplifier gain isolation.
High-temperature annealing of the SiO2/GaAs system
Authors: Ohdomari Iwao , Mizutani Shuzo , Kume Hitoshi , Mori Mutsuhiro , Kimura Itsuro , Yoneda Kenji
Published: February 2003

A neutron activation technique has been used to analyze the gallium content in SiO2 films deposited on n-type GaAs. Gallium was observed in the SiO2 films after annealing at temperatures between 730 and 940 °C. It is found that the surface of GaAs reacts with the H2O in the SiO2 films and/or ambient gas via pinholes at these high temperatures. The reaction is influenced by the partial pressure of water in the ambient gas.
Sensitive optoacoustic detection of carbon monoxide by resonance absorption
Authors: Gerlach Robert , Amer Nabil M.
Published: February 2003

Sensitive (0.15 ppm) and unambiguous detection of carbon monoxide is reported and a comparison of acoustically resonant and nonresonant detectors is given. The pressure dependence of the optoacoustic signal is discussed in the context of atmospheric absorption.
Isotopically selective ir photodissociation of SeF6
Authors: Tiee Joe J. , Wittig Curt
Published: February 2003

The isotopically selective ir photodissociation of SeF6 is reported. The output from an NH3 laser (780.5 cm−1, 50 mJ, 200 nsec FWHM) is used to photodissociate SeF6, and the five abundant isotopes of Se are all enriched despite the rather small (∼1.6 cm−1/amu) isotope shift of the ν3 vibration. These results are predictable using a simple empirical technique which can be applied equally well to the ir photodissociation of other molecules.
A microwave GaAs insulated gate FET
Authors: Lile D. L. , Collins D. A. , Messick L. , Clawson A. R.
Published: February 2003

Microwave power gain has been obtained in MIS gated field effect transistors (FET’s) made on n-type GaAs with 4-μm gate lengths. The magnitude of this gain is comparable to that observed with similar geometry Schottky gate devices.
Current-voltage characteristics and deep levels in chromium-doped semi-insulating GaAs
Authors: Kitahara K. , Nakai K. , Shibatomi A. , Ohkawa S.
Published: February 2003

It is deduced from the correlation among current-voltage characteristics, photoconductivity spectra, and Fermi-level energy that the current-voltage characteristics of chromium-doped semi-insulating GaAs are dominated by the concentration ratio of the deep level related with chromium to the deep level related with oxygen. This correlation is explained by a space-charge-limited current model.
Sensitivity of the T
c of Nb3Ge to hydrogen content
Authors: Lanford W. A. , Schmidt P. H. , Rowell J. M. , Poate J. M. , Dynes R. C. , Dernier P. D.
Published: February 2003

Sputtered Nb3Ge films are doped with hydrogen by exposing them to acid and the effects of this hydrogen are studied. The hydrogen content of these films is measured using the 15N nuclear resonance profiling method. Hydrogen incorporated at concentrations up to 1.8×1022 cm−3 (23 at.%) expands the lattice up to 2.5% and depresses the superconducting transition temperature Tc, ∼1 K per 1021 H atoms/cm3. Hydrogen is also found in as-sputtered films, the amount increasing as the film deposition temperature is reduced.
Strong magnetic relaxation of tetravalent iron ions in calcium-doped yttrium iron garnet films
Authors: Borghese Camillo , Cosmi Roberto , De Gasperis Paolo , Tappa Remo
Published: February 2003

Ferromagnetic resonance relaxation has been used to study a series of LPE-grown YIG films containing calcium in increasing concentrations. The considerably large linewidths revealed that a high population of Fe4+ ions is allowed to enter the epilayers. Etching techniques and selective heat treatments provided respectively an insight on the Ca-concentration gradients within the films and a means of confirming the identification of the relaxing ions.
Third-order nonlinear susceptibility ratio by CARS of mixtures: CS2 in C6H6
Authors: Wiener-Avnear E. , Chandra S. , Compaan A.
Published: February 2003

A precise value of the third-order nonresonant susceptibility ratio of carbon disulphide to benzene is determined from coherent anti-Stokes Raman scattering (CARS) experiments in mixtures of the two liquids. The value is derived from the variation of the frequency separation between the Raman resonance and the interference minimum as a function of the relative concentration of the liquids. The method offers special advantages in many situations of interest.
Optoacoustic detection of sulphur dioxide below the parts per billion level
Authors: Koch K. P. , Lahmann W.
Published: February 2003

We report a novel optoacoustic detection scheme which is suited for use with low-power radiation sources. The improved detection capability is demonstrated for SO2 with a frequency-doubled dye laser of 1 mW uv output power, allowing the detection of SO2 concentrations as low as 0.12 ppb.
High-power fundamental-transverse-mode strip buried heterostructure lasers with linear light-current characteristics
Authors: Tsang W. T. , Logan R. A. , Ilegems M.
Published: February 2003

A new laser structure, the strip buried heterostructure (SBH) laser, using an active layer strip 2.5 to 10 μm in width, on a low-loss waveguide is described. Typical test results with pulsed injection, for a 5-μm strip width, show stable fundamental-transverse-mode operation linear light-current characteristics up to 15 times threshold where the power output is 230 mW/mirror (without AR coating). Single-longitudinal-mode oscillation has also been observed up to twice threshold. Far-field beam divergence of 8°–10° and 26°–30° was obtained in directions parallel and perpendicular to the junction plane, respectively.
Incoherent mirrorless bistable optical devices
Authors: Garmire E. , Marburger J. H. , Allen S. D.
Published: February 2003

A new class of bistable optical devices is described which do not require resonators or single-mode lasers. Optical bistability was demonstrated using a LiNbO3 electro-optic modulator and a multimode laser.
Surface to bulk mode conversion at interfaces on y-z LiNbO3
Authors: Goruk W. S. , Stegeman G. I.
Published: February 2003

The angular spectra of bulk waves mode converted from surface wave reflections at a free-metallized, mass-loaded, and 90° crystal corner interface were measured on y-z lithium niobate. The fraction of surface acoustic wave energy converted into shear bulk wave energy was dependent on the strength of the surface perturbation at the interface.
Diffuse x-ray scattering from small defects in a very perfect silicon single crystal
Authors: Harada Jimpei , Wakamatsu Katsuei , Yasuami Shigeru
Published: February 2003

Two kinds of diffuse x-ray scattering were found in a very perfect silicon single crystal. One of them forms a cigar shape, extending along the [111] direction. The other is a disk shape whose normal is also parallel to the [111] direction in reciprocal space. Both diffuse scatterings are predominant along the crystal pulling [111] direction. From simple Fourier inversion of the shapes of the diffuse scatterings, it is concluded that the platelike defects and needlelike defects are the origins of the diffuse scatterings. The platelike defects observed differ from those observed by Patel for Czochralski silicon with heat treatment.
Ar2F* radiative lifetime measurement
Authors: Chen C. H. , Payne M. G.
Published: February 2003

Time-resolved and time-integrated spectra for Ar-F2 mixtures excited by proton beams with various F2 pressures are obtained to determine the lifetime of Ar2F*. The quenching rate constant of Ar2F* by F2 is also reported.
Arsenic and gallium distribution coefficients in liquid-phase epitaxial GaxIn1−xPyAs1−y
Authors: Coleman J.J.
Published: February 2003

Data are presented on liquid-phase epitaxial (LPE) GaxIn1−xPyAs1−y in the composition range (0.5<y<0.9) grown on InP substrates which indicate the nature of the compositional dependence of As and Ga distribution coefficients. The distribution coefficient functions when extrapolated to lattice-matched compositional limits (y=0,1) are consistent with published data on those limits.
Collisionless production of C2(a3πu) in an intense infrared laser field
Authors: Campbell J. D. , Yu M. H. , Wittig C.
Published: February 2003

It is shown that C2 is formed in the a3πu state via the ir photodissociation of selected polyatomic molecules in the absence of collisional processes.
The photoinitiated impulse-enhanced electrically excited (PIE) discharge for high-power cw laser applications
Authors: Seguin H. J. J. , Nam A. K. , Tulip J.
Published: February 2003

The application of high-repetition-rate photoionized TEA laser techniques to continuous wave CO2 lasers is described. A PIE discharge approach is shown to provide a simple and convenient method for production of uniform large-volume high-density plasmas, suitable for continuous high-powered CO2 laser operation. The approach may be suitable for discharge-pumped noble-gas–halide lasers.
Ultraviolet absorption of CF3I induced by excitation of the ν1 vibrational mode at 9.6 μm
Authors: Pummer H. , Eggleston J. , Bischel W. K. , Rhodes C. K.
Published: February 2003

The broadening of the absorption profile for photolytic production of I (2P01/2) from CF3I under conditions for which the CF3I is vibrationally excited by 9.6-μm R-branch lines of a CO2 laser is investigated. Broadening is observed by measuring the absorption of Kr+ ion laser lines at 3500 and 4100 Å in the vibrationally excited gas. We report ultraviolet absorption data corresponding to several infrared excitation frequencies in a pressure range of CF3I from 0.03 to 3 Torr.
Hg0.7Cd0.3Te charge-coupled device shift registers
Authors: Chapman R. A. , Kinch M. A. , Simmons A. , Borrello S. R. , Morris H. B. , Wrobel J. S. , Buss D. D.
Published: February 2003

Eight-bit CCD shift registers with 10-μm-long electrodes have been successfully fabricated on n-type Hg0.7Cd0.3Te and operated between temperaures of 77 and 140 K. At 77 K, a charge transfer efficiency of 0.996 was obtained under four-phase operation between 1 and 100 kHz clock frequencies. The input signal was provided by pulsing an input gate beyond the tunnel breakdown limit during the on-time of the phase-one potential well. Signal was detected using a floating-gate output followed by correlated double sampling. The size of the signal is in agreement with predictions.
Hydrogenation and dehydrogenation of amorphous and crystalline silicon
Authors: Pankove J. I. , Lampert M. A. , Tarng M. L.
Published: February 2003

The dehydrogenation of amorphous silicon leaves dangling bonds which can be rehydrogenated by exposure to atomic H, but not to undissociated H2. The hydrogenation of dangling bonds in crystalline Si was monitored via the I (V) characteristics of a p-n junction.
Measurements of the electronic and nuclear contributions to the nonlinear refractive index of beryllium fluoride glasses
Authors: Weber M. J. , Cline C. F. , Smith W. L. , Milam D. , Heiman D. , Hellwarth R. W.
Published: February 2003

The nonlinear refractive-index coefficient n2 of three beryllium fluoride glasses was measured at 1064 nm using time-resolved interferometry. The refractive-index nonlinearity of amorphous BeF2 is the smallest reported for any solid. From Raman scattering spectra, the nuclear contribution n2 was found to be ≈20–30% of the total, a factor similar to that for oxide glasses.
Very low threshold Ga(1−x)AlxAs-GaAs double-heterostructure lasers grown by metalorganic chemical vapor deposition
Authors: Dupuis R. D. , Dapkus P. D.
Published: February 2003

Room-temperature Ga(1−x)AlxAs-GaAs DH lasers with very low threshold current densities have been grown by metalorganic chemical vapor deposition (MO-CVD). Devices have been fabricated with thresholds lower than the best values reported for comparable devices grown by liquid-phase epitaxy. The lowest threshold achieved is 590 A/cm2 for a laser with an active layer thickness of d=1100 Å and Ga(1−x)AlxAs confinement layers with x∼0.50.
Grating reflector for a thin-film Fabry-Perot laser
Authors: Hsu T. Y. , Tuan H. S.
Published: February 2003

The reflection- and radiation-loss characteristics of a periodic grating reflector array for a thin-film Fabry-Perot laser are treated using a perturbation approach combined with the coupled mode theory. The present treatment derives the array properties directly in terms of the grating geometry and material constants of the thin-film guide. It also provides quantitative information on the reflection coefficient and reflector power loss resulting from mode conversion into radiation.
Anomalous temperature dependence observed on the photovoltage of Se-based amorphous thin film–SnO2 heterostructures
Authors: Nang Tran Tri , Okuda Masahiro , Matsushita Tatsuhiko , Suzuki Akio
Published: February 2003

The temperature dependence of the photovoltage of Se-based amorphous thin film–SnO2 heterostructures has been studied over a temperature range of 77–393 °K. An anomalous temperature dependence of the photovoltage was observed, i.e., for a constant light intensity, the photovoltage initially increases with increasing temperature, reaches a maximum value at some temperature, and therefore decreases with further increase in temperature.
A microwave InP/SiO2 MISFET
Authors: Messick L. , Lile D. L. , Clawson A. R.
Published: February 2003

Microwave power gain of insulated gate field-effect transistors (FET’s) fabricated with 4-μm gate lengths on n-type InP is reported. The gain is comparable to that of GaAs Schottky gate devices of identical geometry.
Stimulated emission of surface plasmons by electron tunneling in metal-barrier-metal structures
Authors: Siu D. P. , Gustafson T. K.
Published: February 2003

We show that correlation currents arising from the superposition of pairs of states on distinct sides of a potential barrier in metal-barrier-metal structures can result in inelastic tunneling through the emission of surface plasmons. Net gain of an externally excited plasmon field is possible.
Observations of anisotropic diffused layer sheet resistance in EFG silicon ribbon solar cells
Authors: Serreze H. B. , Ravi K. V. , Hari Rao C. V.
Published: February 2003

Anisotropic electrical conductivity has been observed in the near-space-charge region of phosphorus-diffused EFG silicon ribbon solar cells during the course of junction profiling studies using Van der Pauw sheet-resistance measurement techniques. This anisotropy is believed due to either preferential diffusion of phosphorus down linear defect boundaries which are present in EFG silicon or to dislocation pile-up along these boundaries.
The core structure of extrinsic stacking faults in silicon
Authors: Krivanek O. L. , Maher D. M.
Published: February 2003

The core structure of oxidation-induced extrinsic stacking faults in silicon has been studied by high-resolution transmission electron microscopy. The stacking faults were viewed edge-on in thin (011) crystals so that two sets of (111) lattice planes were imaged simultaneously. The images confirm the stacking sequence A‖aCcB‖b (vertical bars denote twinning planes) that was predicted by Hornstra for the stacking-fault core.
Experimental ferroelectric domain wall motion devices
Authors: Geary J. M.
Published: February 2003

A new class of devices employing the controlled motion of individual domain walls in a ferroelectric single crystal is outlined. Unlike older ferroelectric devices, these devices make no use of any coercive threshold. A working prototype device capable of logic and pulse amplification is presented. An analog readout device is described which is capable of repeatedly generating a fixed waveform of substantial complexity and length. An experimental device of this kind and its resulting waveforms are presented. Other devices including shift register memories and optical area scanners are briefly mentioned.
Plasma production experiments using a pulsed HF laser
Authors: Dyer P. E. , Sayers J. A. , Salvetti G.
Published: February 2003

A high radiance unstable resonator HF laser (λ=2.8 μm) has been used to produce plasmas from Al and C targets in a vacuum. Measurements of the plasma properties at irradiance levels up to 7×1010 W cm−2 have been made using a range of diagnostic techniques (x-ray detectors, charge probes, streak photography, and plasma reflection).
Spatially controlled crystal regrowth of ion-implanted silicon by laser irradiation
Authors: Celler G. K. , Poate J. M. , Kimerling L. C.
Published: February 2003

We demonstrate the unique capability of a repetitively pulsed laser to ’’write’’ a monocrystalline pattern in ion-implanted amorphous silicon layers. Ion-channeling data, from the samples scanned with a focused beam of a Q-switched Nd : YAG laser, show a continuity of the single-crystal layer produced with spatially overlapping laser pulses, at 60–80 MW cm−2. Scattering yields indicate very high substitutionality of the implanted ions and an interdependence between the laser power density and the depth redistribution of the implants. Finally, similar recrystallization was obtained with a CO2 laser at 10.6 μm.
Oscillation phenomenon in ThO2-doped SnO2 exposed to CO gas
Authors: Nitta Masayoshi , Kanefusa Shinji , Taketa Yoshiaki , Haradome Miyoshi
Published: February 2003

In the ThO2-doped SnO2 a new self-oscillation phenomenon has been found only when it is exposed to CO gas. This phenomenon is related to the environmental CO gas concentration, substrate temperature, and applied voltage. The oscillation is extremely senstivie to the concentration of CO gas, especially in the region of 0.2-0.3%.
Reflection of resonance cone and plasma-filled waveguide modes
Authors: Gonfalone A.
Published: February 2003

The resonance cone excited by a radio-frequency antenna in a magnetoplasma is investigated in a large metallic plasma chamber. The large number of reflections of the resonance cone is found to be the explanation for the extensively observed and studied ’’Trivelpiece-Gould’’ modes for a plasma-filled waveguide. A dispersion relation is found, in close agreement with previous studies, which describes accurately the experimentally observed wavelike structures.
On the use of photoacoustic cell for investigating the electron-phonon interaction in semiconductors
Authors: Ghizoni C. C. , Siqueira M. A. A. , Vargas H. , Miranda L. C. M.
Published: February 2003

By exploring the simple periodic heat-flow principle of the photoacoustic cell we demonstrate experimentally the usefulness of the acoustic cell for studying the transport properties of semiconductors. An interesting feature of this technique is that it allows us to separate the different sources of sound generation in a semiconductor. Specific application is made for the case of Si crystals submitted to rectangular voltage pulses.
Ion-implanted n-channel InP metal semiconductor field-effect transistor
Authors: Gleason K. R. , Dietrich H. B. , Henry R. L. , Cohen E. D. , Bark M. L.
Published: February 2003

Device-quality n-type layers have been produced by ion implantation in Fe-doped semi-insulating InP. 29Si has been used as the dopant and anneals were carried out with the aid of a multiple-layered encapsulant consisting of plasma-deposited Si3N4 and pyrolytic P-doped SiO2. These layers have been used to make n-channel MESFET’s for which gains of 13.7 and 9.8 dB were measured at 8 and 10 GHz, respectively. The gate metallization for these devices was Au. Low-leakage currents and adequate gate breakdown characteristics were observed.
Room-temperature operation of distributed-Bragg-confinement Ga1−xAlxAs-GaAs lasers grown by metalorganic chemical vapor deposition
Authors: Dupuis R. D. , Dapkus P. D.
Published: February 2003

Room-temperature operation of new type of Ga1−xAlxAs-GaAs laser employing distributed Bragg reflectors for optical and carrier confinement has been demonstrated. These distributed-Bragg-confinement lasers are grown by metalorganic chemical vapor deposition and exhibit low-threshold current densities and small angular beam divergence.
The observation of transients in a CO2 or N2O ir laser by modulation of an intracavity absorber
Authors: Arimondo E. , Glorieux P.
Published: February 2003

A damped oscillation following a stepwise modulation of an intracavity saturable absorber has been observed in the output power of an infrared CO2 and N2O laser. A high frequency of oscillation (∼100 kHz) and a large damping rate were observed for a high laser power and, when the laser power was lowered, both were reduced with the damping rate becoming zero as the laser started passive Q switching. The smooth variation of the characteristics into the passive Q-switching region indicates that the damped oscillation is caused by the same mechanism which causes the passive Q switching, that is, the exchange of radiative energy between the laser gain medium and the saturable absorber. For a laser operating in the low-power regime, a narrow resonance has been observed in the laser modulation depth when the frequency of the stepwise modulation was varied continuously from 10 to 100 kHz. This resonance can be used effectively for increasing the sensitivity of intracavity laser spectroscopic experiments.
Polyacetylene, (CH)x: n-type and p-type doping and compensation
Authors: Chiang C. K. , Gau S. C. , Fincher C. R. , Park Y. W. , MacDiarmid A. G. , Heeger A. J.
Published: February 2003

A series of experiments are reported which demonstrate that donors or acceptors can dope polyacetylene to n type or p type, respectively, and that the two kinds of dopants can compensate one another. The formation of a rectifying p-n junction is demonstrated. These results suggest the possibility of utilizing doped polyacetylene in a variety of potential semiconductor device applications.
Iron pentacarbonyl photodissociation laser
Authors: Trainor Daniel W. , Mani Siva A.
Published: February 2003

Laser action was observed when mixtures of Fe(CO)5 and an inert gas were irradiated with a focused beam of KrF laser photons (λ=248 nm). Single-pass amplified spontaneous emission was observed in two wavelength regions: the near uv and the yellow-green. Measurements made with narrow bandpass filters showed nearly 60% of the output photons were at 385 nm.
Bragg switch for optical channel waveguides
Authors: Chen B. , Meijer C. M.
Published: February 2003

An optical switch based on the deflection of optical beams between two crossed channel waveguides by an electro-optic grating was designed and tested. The waveguide medium is Ti-diffused LiNbO3. At 30 V applied voltage, 92% depletion in the original channel and 48% deflection in the deflected channel was obtained.
Two-photon- and x-ray-induced Nb4+ and O− small polarons in LiNbO3
Authors: Schirmer O. F. , von der Linde D.
Published: February 2003

ESR investigations show that two-photon excitation and x irradiation of nominally pure LiNbO3 crystals at 20 K create electrons, which are self-trapped as Nb4+, and holes, which are captured at acceptor-type defects as O−. The radiation-induced absorption at low temperatures is attributed to these centers. The trapped electrons and holes play an important role in the two-photon-induced photorefractive process.
High temperature single-mode cw operation with a junction-up TJS laser
Authors: Kumabe Hisao , Tanaka Toshio , Namizaki Hirofumi , Ishii Makoto , Susaki Wataru
Published: February 2003

A modified TJS laser has been developed, in which the current is effectively confined to the active region. When heat sinked through the substrate, the laser operates continuously at over 100 °C in a single longitudinal and fundamental transverse mode.