bluuebunny/crossref_metadata_2025 huggingface dataset:
Intensity modulation in GaAlAs metal-gap channel waveguides
Authors: Reisinger A. R. , Bellavance D. W. , Lawley K. L.
Published: February 2003

We report a simple intensity modulator in GaAlAs waveguiding structures. The optical attenuation associated with Schottky-barrier contacts defining metal-gap channels is controlled by an applied voltage. A modulation depth of 88% was measured at a wavelength of 1.06 μm with a bias of 25 V in a device 8.5 mm long.
Identity between spreading and noise diffusion coefficients for hot carriers in semiconductors
Authors: Nougier J. P.
Published: February 2003

It is proved that the three diffusion coefficients, related to noise, spreading of a bunch of carriers, and gradient of concentration, are identical. This demonstrates in the hot carrier regime the validity of the relation kTn(E)/q=D (E)(dvd(E)/dE)−1 which is an extension of the Ohmic Einstein relation (Tn is the noise temperature, D is the diffusion coefficient, vd is the drift velocity). Therefore the noise and time-of-flight techniques appear as being two ways which are quite different, leading to the same diffusion coefficient.
Stability of small bits written in amorphous GdCo thin films
Authors: Togami Yuji
Published: February 2003

The experiments on the stability of small bits in amorphous GdCo thin films under changes of the external magnetic field and the temperature were performed. It is concluded that the bits written in films which are inhomogeneous along the film thickness are stable. No deterioration for the thermomagnetic and magneto-optic application could be found in these films.
Analytic approximations for the Fermi energy in (Al,Ga)As
Authors: Joyce W. B.
Published: February 2003

Simple analytic procedures are given for finding the Fermi energy in a semiconductor with a parabolic or nonparabolic band structure, and (Al,Ga)As is treated as an example of a nonparabolic material in which each of the three conduction bands, Γ, L, and X, competes effectively for electrons. The electron and hole Fermi energies form the basis for determining the voltage and further electrical characteristics of a semiconductor device.
Crystalline defects in solid phase epitaxy Si films deposited at elevated temperatures
Authors: Christou A. , Davey J. E. , Tseng W.
Published: February 2003

Si layers deposited on Au-Si substrates at temperatures above 380 °C are epitaxial with the underlying Si substrate. The layers analyzed contain a high density of microtwins which is the main factor resulting in dechanneling in the aligned RBS spectrum. The deposited layers also contain stacking faults and residual Au inclusions adjacent to primary twins.
Origin of coercivity in a Cr-Co-Fe alloy (chromindur)
Authors: Mahajan S. , Gyorgy E. M. , Sherwood R. C. , Jin S. , Nakahara S. , Brasen D. , Eibschutz M.
Published: February 2003

Lorentz microscopy and magnetization and Mössbauer effect measurements have been performed on a Cr-Co-Fe alloy having a two-phase microstructure. Domains spanning many particles have been seen in samples whose Hc’s vary between 200 and 420 Oe. Walls appear to be ragged and are held back by particles. Magnetization and Mössbauer effect measurements indicate that the two phases constituting the microstructure in each of the three situations examined are ferromagnetic at ambient temperature. Based on these results it is inferred that domain-wall–particle interaction is responsible for Hc.
Efficient metal hydride arc source
Authors: Slafer W. D. , Benard D. J.
Published: February 2003

Intense visible emission from Ca and Mg hydrides in an rf-excited heat pipe oven was produced with electrical efficiencies up to 5%, suggesting possible use as an efficient narrow-band light source.
Impedance characteristics of heated REB diodes
Authors: Johnson D. J.
Published: February 2003

The influence of anode and cathode plasma upon the behavior of low-impedance REB diodes is investigated by acquiring data with anodes and cathodes heated to 1000 and 200 °C, respectively. These data indicate a reduction in impedance collapse which is consistent with a 20% reduction in the anode-cathode plasma gap closure velocity and a factor of 2.5 reduction in ion current. The ion current is reduced for heated anodes because then the ion current is primarily attributed to weakly ionized carbon and higher atomic number ions rather than protons.
Strong electromechanical coupling of SAW on a Pb2KNb5O15 single crystal
Authors: Yamauchi Hisao
Published: February 2003

Surface-acoustic-wave (SAW) characteristics of a lead potassium niobate (Pb2KNb5O15) single crystal have been calculated. It is predicted that SAW on this material has very strong electromechanical coupling 2Δv/v of more than 10% in the stiffened Rayleigh mode in the X-axis boule and Y-cut plate and as high as 28.5% in the Bleustein-Gulyaev mode in the Z-axis cylinder.
Absorption in Ne- and Ar-rich XeF* laser mixtures
Authors: Rokni M. , Jacob J. H. , Mangano J. A.
Published: February 2003

The absorption in e-beam-pumped Ar/Xe/F2 and Ne/Xe/F2 mixtures was measured using a flashlamp-pumped dye laser at 340 nm. The photoabsorption of the active medium affects the extraction efficiency and the length scaling of the laser. The gas mixtures were excited by a 150-keV 5-A/cm2 beam of fast electrons. The pumping conditions and gas mixtures used were typical of e-beam-pumped XeF lasers. Our results confirm that the absorption in Ne-diluted mixtures is appreciably smaller than in Ar-diluted mixtures. Data was obtained for a wide variety of mixture pressures and ratios. Using our kinetic model, the results were analyzed and the dominant absorbing species were identified.
Dynamic Stark-tuned FIR lasers in Rb
Authors: Chang T. Y. , Damen T. C. , Nguyen V. T. , McGee J. D. , Bridges T. J.
Published: February 2003

Superfluorescent FIR lasers near 50 μm in Rb vapor have been tuned over 800 MHz by using the dynamic Stark effect induced by a Q-switched CO2 laser beam. The latter is nearly resonant with a transition involving the lower level of the FIR laser. A tuning range of several cm−1 should be possible by using a TEA CO2 laser.
Branching waveguide coupler in a GaAs/GaAlAs injection laser
Authors: Scifres D. R. , Burnham R. D. , Streifer W.
Published: February 2003

A branching waveguide coupler is fabricated by preferential liquid-phase epitaxial growth. This structure provides optical coupling of the laser light into a passive waveguide and provides single longitudinal mode operation for the laser.
Dual-beam laser: A GaAs double-cavity laser with branching output waveguides
Authors: Merz J. L. , Logan R. A.
Published: February 2003

A new GaAs injection laser is reported with dual output beams at one mirror. The device is fabricated by incorporating a branching taper in the optical cavity. Minor changes in the layer parameters allow device operation either as a power divider or a mode splitter. One dominant longitudinal mode with suppression of unwanted structure is observed due to coupling of dual optical cavities.
Josephson-effect absolute noise thermometer: Resolution of unmodeled errors
Authors: Soulen R. J. , Giffard R. P.
Published: February 2003

An absolute cryogenic temperature scale is being defined at the National Bureau of Standards using the linewidth of radiation emitted by a resistively shunted Josephson junction. We report careful measurements of the impedance of this noise thermometer and show that its behavior is in excellent agreement with the predictions of the resistively shunted junction model assuming a sinusoidal current-phase relationship. The implications for absolute noise thermometry are discussed.
Quantification of atom-probe FIM data and an application to the investigation of surface segregation of alloys
Authors: Tsong T. T. , Ng Yee S. , Krishnaswamy S. V.
Published: February 2003

It is shown that the atom-probe field-ion-microscope data does not give directly the true composition of a sample. A method is devised for converting the data to the true composition. We also report here the first ToF atom-probe study of surface segregation of Pt–5% Ru and Pt–8% W alloys. Using the new analysis the true composition depth profiles of the alloys are obtained with a single atomic layer resolution.
Free-electron momentum modulation by means of limited interaction length with light
Authors: Pantell R. H. , Piestrup M. A.
Published: February 2003

An analysis is performed to determine the energy exchange between light and free electrons when the interaction length is limited. Restricting the length introduces a momentum uncertainty which can be sufficient to allow energy transfer in vacuum if the particles are relativistic and the angle between the direction of particle motion and light wave vector is small.
The effect of the cyclotron resonance on the sensitivity of a glow discharge to millimeter-wave radiation
Authors: Opher R. , Politch J. , Felsteiner J.
Published: February 2003

The sensitivity of a miniature glow discharge tube to electromagnetic millimeter-wave radiation (70 GHz) was investigated in magnetic fields near the cyclotron resonance. A 100-fold increase in the signal-to-noise ratio (SNR) was obtained at the cyclotron resonance. The SNR of the tube at cyclotron resonance was greater than ten times that of a commonly used crystal detector for millimeter-wave radiation (1N53D) measured under similar conditions.
Photocapacitive MIS infrared detectors
Authors: Sher A. , Crouch R. K. , Lu S. S.-M. , Miller W. E. , Moriarty John A.
Published: February 2003

A new class of room-temperature infrared detectors, which exploits the photocapacitive effect in MIS and MISIM devices, is reported. An (unoptimized) peak detectivity of ∼3×1012 W−1 cm Hz1/2 has been measured in a prototype Si device.
Improvement in energy extraction by a multiline/double-band CO2 laser
Authors: Kawamura Y. , Takeda H. , Fujita H. , Matoba M. , Nakai S. , Yamanaka C.
Published: February 2003

For short-pulse energy extraction from a CO2 laser amplifier it is desirable to use multiline/double-band amplification. Multiline/double-band oscillation including up to nine lines was obtained simultaneously from the 9.6- and 10.6-μm bands by placing an etalon perpendicular to the optical axis of a CO2 laser and adjusting its thickness in the oscillator cavity. Improvement in energy extraction was corroborated in the region of saturation amplification using a 1-atm electron-beam-controlled amplifier.
Sealed multiatmosphere CO2 TEA laser: Seed-gas compatible system using unheated oxide catalyst
Authors: Gibson R. B. , Javan A. , Boyer K.
Published: February 2003

A sealed multiatmospheric CO2 TEA laser is reported in which recombination of principle discharge products CO and O2 is induced by recirculating the laser gas mixture through a room-temperature oxide catalyst bed. No special gas mixtures are required and the catalyst is compatible with at least some trialkylamine seed gases.
Gettering of surface and bulk impurities in Czochralski silicon wafers
Authors: Rozgonyi G. A. , Pearce C. W.
Published: February 2003

The ability of SiO2 precipitates to act as a source of process-induced defects which can either beneficially getter unwanted impurities, or deleteriously interact with surface devices, has led to some confusion in interpreting the role of wafer oxygen content in device processing. This report presents a composite model which explains the many variables involved in oxygen precipitation and gettering phenomena.
Polarization-dependent energy transport in laser-produced plasmas
Authors: Pearlman J. S. , Thomson J. J.
Published: February 2003

The polarization dependence of the ion expansion from the front and rear of laser-irradiated thin-film targets is measured. The thermal ion component shows an increased asymmetry with incident p polarization compared with s-polarized radiation. This is attributed to reduced thermal conductivity. Various possible mechanisms for this effect are discussed.
Stability criteria in metal vapor discharges
Authors: Srivastava B. N. , Jacob J. H. , Mangano J. A. , Rokni M.
Published: February 2003

In this letter we discuss the stability criteria in recombination- and attachment-dominated metal vapor laser discharges. The mercury halide laser discharges are typical of attachment-dominated discharges, while the metal vapor exciplex lasers, like CdHg*, are typical of recombination-dominated discharges. In high-power electronic transition laser discharges, a relatively large excited-state population exists which dominates the stability of these discharges. This occurs because the excited states have a smaller ionization potential and larger ionization cross section than the ground state. As a result, multistep ionization is the dominant ionization. When three-step ionization is dominant and electron mixing of the excited states is unimportant, attachment-dominated discharges will be stable if the attachment rate β⩾mνi0, where 2<m⩾3 and νi0, is the equilibrium ionization rate. For a recombination-dominated discharge the criterion in this limit is ane0⩾mνi0 where 1.0<m⩾1.5 and a is the recombination coefficient and ne0 is the equilibrium electron density.
Sidewall penetration of dislocations in ion-implanted bipolar transistors
Authors: Koji T. , Tseng W. F. , Mayer J. W.
Published: February 2003

Phosphorus-doped emitters have been formed by either conventional diffusion or implantation, anneal, and drive-in processes. Transmission electron microscopy and measurements of transistor characteristics were made to evaluate the two processes. Comparison of structures with similar dislocation densities indicated that the dislocations in the implanted structures penetrated the emitter-base sidewall, whereas the dislocations in the diffused structure were confined to the emitter region. The transistor with extended dislocations exhibited high leakage current and excess popcorn noise generating.
Surface composition and fabrication of an oxide-free Ga1−xAlxAs Schottky barrier
Authors: Lee Bansang W. , Mark Peter , Yeh Jwu-Lin
Published: February 2003

A native oxide layer of ∼30 Å is found on the Ga1−xAlxAs surface. Ion-sputtering and ultrahigh vacuum (UHV) technologies are developed to fabricate an oxide-free Schottky barrier from the (100) face of the compound semiconductor.
Effect of groove-depth variation on the performance of uniform SAW grooved reflector arrays
Authors: Parekh J. P. , Tuan H. S.
Published: February 2003

Computations of the variation with groove depth of the SAW scattering properties of a uniform shallow-grooved reflector array are reported for an equivalent isotropic elastic substrate representing Y-cut Z-propagating LiNbO3. In agreement with previous qualitative conclusions based on experimental studies of SAW grooved resonators, the present computations indicate the existence of an optimum groove depth yielding maximum array SAW reflectivity. This optimum groove depth is a monotonically decreasing function of the total number N of grooves in the array. Computed optimum groove depths for various fixed values of N are presented.
Effect of Faraday rotation on stimulated Brillouin backscattering
Authors: Pietrzyk Z. A. , Massey R. S.
Published: February 2003

The suppression of stimulated Brillouin scattering by Faraday rotation in a laser-heated solenoid is examined. Theory and experimental results are compared.
Selective absorption of solar energy in granular metals: The role of particle shape
Authors: Granqvist C. G. , Hunderi O.
Published: February 2003

Coatings for efficient photothermal conversion of solar energy should have high absorption at wavelengths λ<λc and low absorption at λ≳λc, where λc is ∼2 μm. For granular metals, we show by computation that λc depends strongly on the shape of the metal particles. Increasing eccentricity of ellipsoidal grains is seen to displace λc towards the infrared. A similar shift is found also for spherical metallic shells surrounding dielectric cores of increasing size. Some implications for practical absorber surfaces are pointed out.
Degradation of (AlGa)As DH lasers due to facet oxidation
Authors: Yuasa T. , Ogawa M. , Endo K. , Yonezu H.
Published: February 2003

The facet deterioration of (AlGa)As DH lasers by aging was analyzed by Auger electron spectroscopy in combination with Ar sputter etching. It was found that oxide was formed on the laser facet during cw operation, and the oxidation degraded lasers not only in long-term operation but also even at an early stage of operation.
Analysis of propagation characteristic of Bleustein-Gulyaev waves at surface imperfections
Authors: Kawasaki Zen’ichro , Tanaka Kazuo
Published: February 2003

This paper describes a theoretical study of the diffraction of Bleustein-Gulyaev waves at surface imperfections. With the use of the integral representations of the shear-horizontal waves in a semi-infinite piezoelectric material, simultaneous integral equations are obtained. Moment methods are applied in order to solve these equations. To obtain a qualitative idea of the propagation characteristic of Bleustein-Gulyaev waves at surface imperfections, numerical illustrations of the power transmission coefficient, power reflection coefficient, and the scattering power coefficient are shown.
Significance of the channeling surface peak in thin-film analysis
Authors: Kauffman Robert L. , Feldman L. C. , Silverman P. J. , Zuhr R. A.
Published: February 2003

The surface scattering of MeV He+ ions channeled along Si〈100〉 from clean well-characterized Si(100) surfaces is measured. The surface peak intensity, along with other values in the literature, is shown to obey simple scaling laws. For the study of very thin films by backscattering the contribution made by this surface scattering can be important.
Internal cw parametric upconversion
Authors: Falk Joel , See Y. C.
Published: February 2003

The first demonstration of cw parametric upconversion inside a laser’s optical cavity is reported. Infrared radiation λ=3.39 μm was upconverted using a 5145-Å argon laser pump and a lithium niobate crystal.
Hyperfine structure in the electronic spectrum of 127I2 by saturated absorption spectroscopy at 633 nm
Authors: Morinaga A. , Tanaka K.
Published: February 2003

The full hyperfine components of the R (127) line in the 11-5 band and the 10 components of the P (33) line in the 6-3 band of the B←X electronic transition of 127I2 were observed by the saturated absorption spectroscopy using a complex resonator He-Ne laser. The frequency of the laser was locked to each component and the frequency separations of the components were precisely measured. The hyperfine structure of the R (127) line was compared with a model which included both a nuclear electric quadrupole and magnetic hyperfine interactions.
Laser annealing of boron-implanted silicon
Authors: Young R. T. , White C. W. , Clark G. J. , Narayan J. , Christie W. H. , Murakami M. , King P. W. , Kramer S. D.
Published: February 2003

The properties of boron-implanted silicon annealed by high-power Q-switched ruby laser radiation are compared with results obtained by conventional thermal annealing. Laser annealing of the implanted layer results in significantly increased electrical activity, as compared to thermally annealed implanted silicon. This correlates well with transmission electron microscopy and ion-channeling measurements which show a dramatic removal of displacement damage as a result of laser annealing. A substantial redistribution of the implanted boron concentration profile occurs after laser annealing which cannot be explained by thermal diffusion in the solid.
Multilayer light scattering and the laser gyro
Authors: Scott M. L. , Elson J. M.
Published: February 2003

Calculations of the angular distributions of scatter have been carried out using an exponential autocorrelation function for the roughness at the interfaces of a multilayer dielectric mirror. This vector scattering theory indicates that techniques are available to reduce scatter levels.
Polarization interferometry in acousto-optics
Authors: Alippi A. , Palma A. , Palmieri L. , Socino G. , Verona E.
Published: February 2003

A simple polarization interferometry technique is introduced in acousto-optics, which allows a polarization discrimination of the light scattered by acoustic waves, when no strain-induced birefringence is produced by the acoustic perturbation. Results are presented, which are obtained through the use of a Savart plate in detecting light scattered by acoustic surface waves.
Electron-electron effects in the writing and erasing of dual-dielectric charge-storage cells
Authors: Thornber K. K. , Kahng D.
Published: February 2003

We have found an abrupt drop in the capture efficiency of dopant-induced interfacial states in DDC’s when the stored-charge density exceeds 7×1012/cm2. The constancy of this number with electric field strength and with increasing capture efficiency from increased induced-state density suggests Coulombic repulsion ultimately limits writing efficiency. Erasing characteristics are also explained by barrier lowering due to electron-electron repulsion.
Spectral tuning of ArF and KrF discharge lasers
Authors: Loree T. R. , Butterfield K. B. , Barker D. L.
Published: February 2003

Simple prism tuning of a well-passivated double-discharge excimer laser has resulted in tuning ranges of better than 20 Å in both ArF and KrF. Neither tuning is continuous, being interrupted by nonlasing holes in regions of self-absorption. A two-prism dispersive chain results in a linewidth of 1–2 Å for KrF and less than 0.5 Å for ArF.
Infrared four-wave sum and difference frequency generation in liquid CO-O2 mixtures
Authors: Kildal Helge , Brueck S. R. J.
Published: February 2003

Four-wave sum and difference frequency generation of the outputs of two CO2 TEA lasers are demonstrated in liquid CO-O2 mixtures at 77 K. The efficiencies of these processes are enhanced by a two-photon resonance with the CO vibrational mode. A study of the polarization dependence and the line shape of the two-photon resonance is reported together with measurements of the mixing efficiencies. The difference frequency generation process can be phase matched using noncollinear phase matching.
Planarized solid-state epitaxial growth of Si and its effect on Schottky barrier diodes
Authors: Reith T. M. , Sullivan M. J.
Published: February 2003

Planarized solid-state Si epitaxy can be grown controllably from Si-doped Al thin films by first depositing a very thin high-temperature underlay film of pure Al on the substrates. It is proposed that both Si pits, in pure Al contacts and Si mesas, in Si-doped Al contacts, nucleate and grow at local defect sites in the native SiO2 on the Si substrate; elimination of the sites leads to planar Si epitaxy structures. The electrical effect of the planar structures, which are p doped with Al, on n-type Schottky barrier diodes is similar to the thin-layer-plus mesa structures which are characteristic of conventionally processed Si-doped Al Schottky diodes after heat treatment. The planarized structures should, however, lead to more uniform and controllable results.
Optical injection locking and switching of transistor oscillators
Authors: Yen H. W. , Barnoski M. K.
Published: February 2003

In this letter we describe a novel approach of achieving injection locking of solid-state oscillators. This is done by taking an external driving signal to modulate a GaAlAs cw injection laser and then guiding the modulated light output in a fiber waveguide to illuminate the active solid-state component in the oscillator circuit. Experiments were carried out with silicon transistor oscillators with frequency ranging from below 1 kHz up to 1.8 GHz. Optical injection locking was observed not only at fundamental frequencies, but also at various subharmonics with less tolerance in frequency deviation. It is also possible to achieve switching and locking simultaneously in these oscillators.
Light-induced superconducting weak links
Authors: Yeh J. T. C. , Langenberg D. N.
Published: February 2003

An experimental test of the effect of localized light irradiation on superconducting weak links shows behavior in qualitative accord with predictions of Volkov.
Magnetic field reversal induced by an intense rotating electron beam in an initially neutral gas
Authors: Roberson C. W. , Tzach D. , Rostoker N.
Published: February 2003

We find field reversals up to four times the initial field and changes in the magnetic field on the axis of symmetry of 6 kG when a rotating electron beam is injected through a cusp into an initially neutral gas. The change in magnetic field on the axis was found to be independent of the magnetic field. This is shown to be consistent with measurements that the cusp transmission coefficient times the ratio of the azimuthal velocity (Vϑ) to the axial velocity (Vz) is independent of magnetic field.
Temperature coefficient of SAW velocity on epitaxial Li1−xNaxNbO3 thin films
Authors: Staples E. J. , Neurgaonkar R. R. , Lim T. C.
Published: February 2003

Liquid-phase epitaxy of doped Li1−xNaxNbO3 films on LiNbO3 has been performed. Sodium-doped films show a 30% reduction in the temperature coefficient of surface acoustic wave velocity.
Evidence of resonance absorption in laser-produced plasmas from the polarization and angular dependence of high-energy x-ray bremsstrahlung emission
Authors: Luther-Davies B.
Published: February 2003

Measurements are reported of the polarization and angular dependence of the amplitude and ’’temperature’’ of high-energy bremsstrahlung emission from planar copper targets irradiated with 25-psec neodymium laser pulses at 5±2×1014 W/cm2. A resonance in the emission is observed for p-polarized incident radiation at an angle of incidence of 25°. The results indicate the presence of plasma density scale lengths of about 1 μm and 17% absorption due to the resonance absorption mechanism.
Stimulated emission at 9.75 μm following two-photon excitation of methyl fluoride
Authors: Prosnitz D. , Jacobs Ralph R. , Bischel William K. , Rhodes Charles K.
Published: February 2003

Stimulated emission at 9.75 μm has been observed in 12CH3F, corresponding to the 2ν3→ν3 transition, subsequent to two-photon excitation with CO2 laser radiation. Results are presented for the dependence of laser output power as a function of 12CH3F pressure, and for a fixed amount of methyl fluoride, as a function of D2 and Ne diluent pressures.
Curved stripe GaAs : GaAlAs diode lasers and waveguides
Authors: Scifres D. R. , Streifer W. , Burnham R. D.
Published: February 2003

We report room-temperature operation of GaAs : GaAlAs double-heterostructure lasers with curved stripes. The power-output–vs–current curves are linear and free of kinks up to substantial levels. The lasers do not exhibit relaxation oscillations under pulsed operation and have stable near- and far-field patterns. A cleaved laser with a 10-μm-wide stripe containing a 1-mm-radius curve did not exhibit a kink until more than 100-mW/facet output power was obtained under pulsed operation. Lasers of this geometry should prove useful for waveguide coupling in integrated optics and as a discrete source for fiber-optic applications.
A narrow-bandwidth picosecond laser
Authors: Huppert D. , Rentzepis P. M.
Published: February 2003

We have examined the advantages of using Nd3+/YAG as an amplifier for a ∼6 psec FWHM pulse generated by a mode-locked Nd3+/glass oscillator. The Nd3+/glass oscillator pulse is characterized by 100 cm−1 bandwidth at 1060 nm with variable temporal substructure. Passage of this pulse through a Nd3+/YAG rod resulted in wavelength-selected amplification of the specific Nd3+/YAG lines located within the envelope of the Nd/glass pulse. The result is a 100-fold amplified pulse consisting of two bands at 1061 nm and 1064 nm, each <3 cm−1 in bandwidth with an average duration of 6 psec and as low as 4 psec.
Lorentz-Lorenz correlation for reactively plasma deposited Si-N films
Authors: Sinha A. K. , Lugujjo E.
Published: February 2003

Amorphous Si-N films were prepared by reactive plasma deposition from SiH4 and NH3 in a radial flow reactor at 275 °C, and studied using 1.8-MeV 4He+ Rutherford backscattering analysis. The films had a Si/N ratio ranging from 0.75 to 1.5, density from 2.8 to 2.1 g cm−3, and refractive index from 1.9 to 2.3. These data have been correlated using the Lorentz-Lorenz equation, yielding a self-consistent set of electronic polarizabilities αN and αSi. The αSi is found to be a function of the Si/N ratio, indicating the increasing presence of Si-H complexes in off-stoichiometric films.
Chemical vapor deposition of silicon using a CO2 laser
Authors: Christensen C. P. , Lakin K. M.
Published: February 2003

Chemical vapor deposition of polycrystalline silicon is reported in which a CO2 laser is used for substrate heating. With this technique, deposition can be spatially limited to only a small portion of the substrate, and a spatial resolution of 50 μ is demonstrated. Since the reaction chamber and majority of the substrate are at much lower temperatures, premature gas phase reactions and substrate etching are avoided.
Type-II localized interface states and Si surface preparation for Ni, Pt, Al/Si Schottky diodes
Authors: Muret P. , Deneuville A.
Published: February 2003

Evidence for a new class of genuinely localized interface states for Ni, Pt, Al-Si Schottky diodes has been obtained from capacitance-voltage measurements. They are in electrical equilibrium with Si, and have short relaxation times (<10−6 s). They give an exponential contribution to the capacitance which is only weakly sensitive to the silicon surface preparation and exhibits a smooth variation with the nature of the metal. These features are consistent with the existence of a Si conduction band tail in the vicinity of the interface as predicted by Inkson.
Low-temperature sputter deposition of high-T
c superconducting niobium-germanium films
Authors: Buitrago R. H. , Toth L. E. , Goldman A. M. , Schwanebeck J. , Dayan M.
Published: February 2003

Sputter-deposited ’’Nb3Ge’’ films have been found to be fully superconducting at temperatures as high as 20.8 K with an onset of 21.8 K. Conditions under which high-Tc films were formed were unique in that the highest Tc’s were obtained at deposition temperatures nearly 200 °C lower than previously reported.
Chemical control of optical damage in lithium niobate
Authors: Holman R. L. , Cressman P. J. , Revelli J. F.
Published: February 2003

A new chemical process has been developed that significantly affects the susceptibility of LiNbO3 crystals and optical waveguiding layers to the laser-induced effects known as optical damage. The process involves controlling the nonstoichiometry of LiNbO3 by diffusion of lithium oxide. Susceptibility to optical damage in bulk crystals was reduced by increasing the nonstoichiometry (out-diffusion) and enhanced by decreasing the nonstoichiometry (in-diffusion). Typically, low-loss optical waveguides formed by the process supported one or more TE modes and tolerated more than 10 kW/cm2 laser transmission at 488.0 nm without inducing any measurable beam profile distortion.
Instability and regenerative pulsation phenomena in Fabry-Perot nonlinear optic media devices
Authors: McCall S. L.
Published: February 2003

Fabry-Perot nonlinear optic devices may undergo regenerative pulsations. Such effects may be used to convert cw laser power into a train of light pulses.
A closed-cycle gas recirculating system for rare-gas halide excimer lasers
Authors: Johnson Philip M. , Keller Norman , Turner Robert E.
Published: February 2003

A closed-cycle recirculating system is described which enables prolonged operation of a rare-gas halide excimer laser on a single charge of rare-gas mixture. The flowing gas is continuously purified in a high-temperature titanium gettering furnace, following removal of the halogen by reaction to form a volatile, but condensable, metal halide. The halogen is reintroduced after the rare-gas purification, being consumed in the operation of the laser along with the gettering metal.
An optical waveguide TE-TM mode splitter
Authors: Kobayashi Morio , Terui Hiroshi , Egashira Kazumichi
Published: February 2003

This letter reports an optical waveguide TE-TM mode splitter using coupling between nonidentical waveguides. The experimental mode splitter was fabricated from glass compositions, and TE0-TM0 mode splitting has been demonstrated.
Accelerated step-temperature aging of AlxGa1−xAs heterojunction laser diodes
Authors: Kressel H. , Ettenberg M. , Ladany I.
Published: February 2003

Double-heterojunction Al0.3Ga0.7As/Al0.08Ga0.92As lasers (oxide-striped and Al2O3 facet coated) were subjected to step-temperature aging from 60 to 100 °C. The change in threshold current and spontaneous output was monitored at 22 °C. The average time required for a 20% pulsed threshold current increases from about 500 h, when operating at 100 °C, to about 5000 h at 70 °C. At 22 °C, the extrapolated time is about 106 h. The time needed for a 50% spontaneous emission reduction is of the same order of magnitude. The resulting ’’activation energies’’ are ∼0.95 eV for laser degradation and ∼1.1 eV for the spontaneous output decrease.
Lyman-α radiation from Cs-H+ and Na-H+ charge transfer processes with a plasma gun
Authors: Haueisen D. C. , Mahr H. , Cassidy J. C. , Tang C. L. , Copeland D. A. , Hartman P. L.
Published: February 2003

Lyman-α radiation due to near-resonant preferred charge transfer in the systems Cs-H+ and Na-H+ was observed for proton fluxes of up to 3×1021 cm−2 sec−1 and alkali densities of up to 1014 cm−3. These results with a plasma gun provide a significant first step towards vuv lasing with such systems.
Direct observation of the saturation behavior of spontaneous emission in semiconductor lasers
Authors: Nakamura M. , Aiki K. , Umeda J.
Published: February 2003

The saturation behavior of the spontaneous emission intensity from a transverse-mode stabilized (GaAl)As laser is studied. The spatial hole burning is observed from the top surface of the laser, and a complete gain saturation is confirmed to occur in the lasing region.
Stabilization of high-gain multipass power amplifiers using saturable absorbers: Experience on the LASL Eight-Beam System
Authors: Montgomery M. D. , Carlson R. L. , Casperson D. E. , Czuchlewski S. J. , Figueira J. F. , Haglund R. F. , Ladish J. S. , Nowak A. V. , Singer S.
Published: February 2003

P-doped germanium and broadband gas absorbers have been used to increase significantly the energy output of the power amplifiers in the LASL Eight-Beam CO2 Laser System. Because they are less easily damaged, gas absorbers are preferred for this application.
Thermally grown silicon nitride films for high-performance MNS devices
Authors: Ito Takashi , Nozaki Takao , Arakawa Hideki , Shinoda Masaichi
Published: February 2003

Amorphous and uniform silicon nitride films with thicknesses of less than 100 Å have been thermally grown on silicon wafers by employing purified ammonia gas. The films are much denser than conventional CVD Si3N4 films. The MNS (metal-thermal nitride-silicon) structures have very low Nss in the order of 3×1010 cm−2 eV−1 and an effective electron mobility of larger than 800 cm2/V sec in the fabricated n-channel MNSFFT.
Measurements of interface state density in MNOS structures
Authors: Arnold Emil , Schauer Henry
Published: February 2003

A technique is described for measuring the density and energy distribution of surface states at the Si-SiO2 interface in MNOS capacitors. The effects of charge injection into the insulator are taken into account by making use of a fast voltage ramp to monitor the instantaneous values of the surface potential during a quasistatic capacitance-voltage sweep. The technique has been used to investigate the effect of charges trapped in the nitride on the interface-state density.
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u x-ray topography of epitaxial Ge layers during growth
Authors: Hagen W. , Queisser H. J.
Published: February 2003

I n situ x-ray topography is used for the study of misfit dislocations in growing heteroepitaxial layers. Topograms taken from Ge layers on GaAs substrates show the generation of misfit dislocations at various locations commencing at a layer thickness of about 1000 Å. These dislocations elongate and eventually grow to a dense cross-grid array. The specially designed epitaxial reactor and the topographic arrangement with a time resolution between 2 and 20 sec are briefly described.
Diffusion lengths in amphoteric GaAs heteroface solar cells
Authors: Ashley K. L. , Beal S. W.
Published: February 2003

Minority-carrier diffusion lengths in amphoteric GaAs : Si were investigated. Electron and hole diffusion lengths in p and n type respectively were determined to be Ln=13 μm and Lp=7 μm. Preliminary efficiency measurements on heteroface structures based on amphoteric GaAs : Si p-n junctions indicated that these devices should make excellent solar cells.
Highly efficient pGaSb-nGa1−xAlxSb photodiodes
Authors: Sukegawa Tokuzo , Hiraguchi Takao , Tanaka Akira , Hagino Minoru
Published: February 2003

Highly efficient pGaSb-nGa1−xAlxSb photodiodes were fabricated by liquid-phase-epitaxial growth of an undoped p-type GaSb layer, followed by that of an n-type Ga1−xAlxSb layer with a composition at x=0.7 on a p-type (100) GaSb substrate. Spectral photocurrent response of the diodes measured at various bias voltages and room temperature was fairly flat between 1.0 and 1.7 μm. The external quantum efficiency of the photoresponse was 38% at zero bias and 54% at 1 V reverse bias in the vicinity of 1.2 μm.
Ion-bombardment-induced transfer of H from N to Si in amorphous Si3N4
Authors: Stein H. J.
Published: February 2003

A transfer of hydrogen from nitrogen to silicon bonds in CVD silicon nitride under N+ and He+ ion bombardment is reported. The amount of H transferred is a function of the ion energy deposited in atomic processes, and the thermal stability of the transferred H is comparable to that for H retained in Si-H bonds during deposition. H transfer is proposed to explain previously reported electrical effects of bombardment-anneal processing of Si3N4 films, and an analogy to H passivation of Si dangling bonds in a-Si is suggested.
Isotopic HCl transfer laser
Authors: Badcock C. C. , Hwang W. C. , Kalsch J. F. , Kamada R. F.
Published: February 2003

An HCl laser that uses isotopic V-V energy transfer collisions as a pumping mechanism has been demonstrated. This multiline laser, which utilized an intracavity cold gas isotope filter, increased the energy from the P1 lines of H37Cl while decreasing the energies of the P1 and P2 lines of H35Cl. Previously unreported lines, including emission from R-branch transitions, have also been observed from single-line HCl and HBr lasers.
Hydrogen and fluorine profiles in GdF3 films measured by sputter-induced optical emission
Authors: Tsong I. S. T. , Bhalla A. S.
Published: February 2003

The sputter-induced optical emission technique has been used to study the classical problem of the exchange of fluorine and hydroxyl ions in a solid. The hydroxyl ions were measured in the form of hydrogen atoms and detected by the characteristic hydrogen emission line at 6563 Å while the fluorine atoms were detected at 6902 Å. Measurement of the optical intensities as a function of sputtering time produced the H and F depth profiles in GdF3 films.
GaAs charge-coupled devices
Authors: Deyhimy I. , Harris J. S. , Eden R. C. , Edwall D. D. , Anderson S. J. , Bubulac L. O.
Published: February 2003

A Schottky-barrier-gate buried-channel GaAs CCD has been successfully demonstrated. A 10-cell (30 gates) three-phase device was operated at room temperature. The device employs a natural channel stop formed by the transfer gates extending from an n-type active region onto a semi-insulating GaAs substrate.
Characterization of silicon layers via guided wave optics
Authors: Olivier Michel , Peuzin Jean-Claude
Published: February 2003

The usefulness of guided wave optics as a tool for characterizing general purpose thin films is demonstrated in two cases of practical interest, i.e., silicon on sapphire and amorphous silicon on glass. Important results are as follows: (i) optical wave propagation at λ=1.15 μm has been observed along a few millimeters in silicon layers; (ii) silicon on sapphire layers show a very high photoelastically induced quasiuniaxial birefringence (Δn≃0.02); (iii) amorphous silicon layers exhibit a nonrectangular index profile, a high birefringence (Δn≃0.02), and finally an anomalously low value of their mean ordinary index (n≃3.04±0.01).
Simplified fabrication of GaAs homojunction solar cells with increased conversion efficiencies
Authors: Fan John C. C. , Bozler Carl O. , Chapman Ralph L.
Published: February 2003

Conversion efficiencies as high as 20% of AM1 have been obtained for single-crystal GaAs shallow-homojunction solar cells without Ga1−xAlxAs layers. These cells, which are fabricated by a simplified technique that does not require any vacuum processing steps, utilize an n+/p/p+ structure with an antireflection coating prepared by anodic oxidation of the n+ layer.
AlGaAs-GaAs double-heterostructure small-area light-emitting diodes by molecular-beam epitaxy
Authors: Lee T. P. , Holden W. S. , Cho A. Y.
Published: February 2003

Small-area high-radiance LED’s fabricated from AlGaAs-GaAs double-heterostructure wafers grown by molecular beam epitaxy are reported. Both oxide-confinement and reverse-biased junctions were employed to confine the injection current to the small light-emitting areas. The series resistance of the diodes was reduced by zinc diffusions into and near the active region and both the linearity and the power saturation characteristics were improved. The interfacial recombination rate was determined to be about 6.6×103 cm/sec. These results are compared with LED’s made by liquid-phase epitaxy.
Influence of molecular dissociation and degree of ionization on rare gas–halide laser properties
Authors: Nighan William L.
Published: February 2003

The influence of F2 dissociation and the accompanying increase in fractional ionization is examined for conditions typical of electron-beam-sustained KrF* lasers. It is found that for electron-density–F2-density ratios greater than about 10−3, rare-gas metastable loss due to electron excitation of higher levels begins to compete significantly with metastable-F2 reactions, thereby leading to a substantial reduction in rare gas–halide production efficiency.
Bandwidth-limited operation of a mode-locked Brillouin parametric oscillator
Authors: Kawasaki B. S. , Johnson D. C. , Fujii Y. , Hill K. O.
Published: February 2003

The radiation in the first Stokes component of a fiber Brillouin parametric oscillator is mode locked. The resultant pulses are stable and bandwidth limited.
Laser modulation of electroluminescence in thin-film ZnS : Mn devices
Authors: Chang I. F. , Yu P. Y.
Published: February 2003

Large photoenhancement (by a factor of ≳100 in some devices) of electroluminescence in thin-film ZnS : Mn devices has been observed near and above the electroluminescence threshold effects when the devices were excited with the near-uv lines of an Ar+ laser. The intensity of the photoenhanced electroluminescence was found to have a sublinear dependence on the laser intensity, saturate, and then decrease with increased laser power.
Instabilities in thin tunnel junctions
Authors: Konkin M. K. , Adler J. G.
Published: February 2003

Tunnel junctions prepared for inelastic electron tunneling spectroscopy are often plagued by instabilities in the 0–500-meV range. This paper relates the bias at which the instability occurs to the barrier thickness.
Low pressure rf annealing: A new technique to remove charge centers in MIS dielectrics
Authors: Ma T-P. , Ma W. H-L.
Published: February 2003

A new technique to effectively anneal out the fixed charge and surface states in various MIS structures is presented. It involves an rf voltage and a low-pressure plasma environment, and employs a concept very different from the conventional thermal annealing. The experimental setup and the requirements pertinent to a successful anneal are described. Some experimental data are shown to demonstrate the effectiveness of this new technique as compared with the conventional thermal anneal. The annealing mechanism is thought to be a plasma-assisted rf field effect aided by a moderate heating of the wafer.
Nonequilibrium response of MOS devices to linearly varying voltages
Authors: Nassibian A. G. , Faraone L. , Simmons J. G.
Published: February 2003

The non-steady-state I-V response of a MOS capacitor subjected to a linear voltage ramp has been studied. The characteristic exhibits structure and is strongly temperature dependent. Furthermore, the characteristic is shown to be a consequence of bulk generation in the silicon, and the parameters of the traps involved in the process are determined.
An InGaAs detector for the 1.0–1.7-μm wavelength range
Authors: Bachmann K. J. , Shay J. L.
Published: February 2003

We report an InGaAs/InP heterojunction detector having high quantum efficiencies in the 1.0–1.7-μm wavelength range. Conditions for growth of the lattice-matched composition by liquid-phase epitaxy at various temperatures are described.
Continuous room-temperature operation of Ga(1−x)AlxAs-GaAs double-heterostructure lasers grown by metalorganic chemical vapor deposition
Authors: Dupuis R. D. , Dapkus P. D.
Published: February 2003

Ga(1−x)AlxAs-GaAs double-heterostructure mesa-stripe-geometry lasers that operate continuously at room temperature (23 °C) have been grown by metalorganic chemical vapor deposition (MO-CVD). Threshold currents as low as 119 mA dc have been measured for devices with a mesa width of 14 μm and a cavity length of 380 μm.
Active fail-safe terminal for fiber-optic data bus
Authors: Soref R. A. , Nelson A. R. , McMahon D. H. , Spillman W. B. , Sheppard L. E.
Published: February 2003

A novel send/receive terminal for multimode fiber bussing has been constructed in an 85-μm-thick LiTaO3 plate forming a curved focusing reflector on the plate end. The low-loss T terminal is an electro-optic switch that requires no light source of its own. It provides maximum optical throughput in the absence of electrical excitation.
GaInAsP/InP avalanche photodiodes
Authors: Hurwitz C. E. , Hsieh J. J.
Published: February 2003

Avalanche photodiodes for detection at 0.9–1.2 μm have been successfully fabricated in epitaxial layers of GaInAsP on InP substrates. Uniform avalanche gains in excess of 12, rise times of 150 psec or less, and low-bias quantum efficiencies of 45% have been measured.
Transition temperature and upper critical field of superconducting V-Al/Cu-Ge composite tapes
Authors: Sekine H. , Togano K. , Tachikawa K.
Published: February 2003

Transition temperature Tc and upper critical field Hc2 were measured for the superconducting composite tapes made by the reaction between a V-Al core and a Cu-Ge matrix. It was found that Tc and Hc2, especially the latter, are significantly increased with increasing aluminum concentration in the vanadium core, reaching 12 K and 170 kOe (at 4.2 K) for the V–18 at.% Al/Cu–9 at.% Ge specimen. This enhancement appears to result from the formation of a V3(Ge,Al) ternary A-15 compound layer.
Exact solutions of the sine-Gordon equation describing oscillations in a long (but finite) Josephson junction
Authors: Costabile G. , Parmentier R. D. , Savo B. , McLaughlin D. W. , Scott A. C.
Published: February 2003

Readily evaluated exact solutions of the sine-Gordon equation are presented for nonlinear standing-wave oscillations on a fixed length of a lossless Josephson transmission line with open-circuit boundary conditions at the ends. Three distinct species of standing waves are described: (i) plasma oscillation, (ii) breather oscillation, and (iii) fluxon oscillation. Fluxon oscillations can absorb power from an external source of bias current; for this case the volt-ampere characteristics relating bias current to average junction have been computed.
An acousto-optic multichannel signal processor
Authors: Lee John N. , Berg N. J. , Udelson B. J.
Published: February 2003

The feasibility of using acousto-optic frequency multiplexing to process several different signals simultaneously has been demonstrated. A four-channel acousto-optical system for correlating signals was operated successfully; each channel had a 45-MHz bandwidth and a minimum of 45-dB channel isolation.