bluuebunny/crossref_metadata_2025 huggingface dataset:
Dye-in-polymer films for ablative optical recording with GaAs diode lasers
Authors: Law K. Y. , Vincett P. S. , Johnson G. E.
Published: February 2003

A high-sensitivity, ablative dye-in-polymer film which can be written and read with a GaAs diode laser has been identified and evaluated. A 105-nm-thick antireflecting film, consisting of 20% of a carbocyanine dye (NK1748) dissolved in poly(vinyl acetate) on an aluminized glass substrate, was ∼3.5 times more sensitive at 835 nm than a 15-nm Te monolayer on a poly(methyl methacrylate) substrate; submicron marks were recorded. The signal contrast (Rf−Ri) /(Rf+Ri) of large marks in the plateau region was ∼0.5. Morphological studies show the expected removal of recording material in the process of mark formation.
Schottky barriers: An effective work function model
Authors: Freeouf J. L. , Woodall J. M.
Published: February 2003

The experimental observations of metallurgical interactions between compound semiconductor substrates and metallic or oxide overlayers have stimulated a new model of Fermi level ’’pinning’’ at these interfaces. This model assumes the standard Schottky picture of interface band alignment, but that the interface phases involved are not the pure metal or oxide normally assumed by other models. For both III-V and II-VI compounds, the barrier height to gold is found to correlate well with the anion work function, suggesting the interface phases are often anion rich. This correlation holds even for cases in which the ’’common anion rule’’ fails, and explains both successes and failures of this earlier model.
cw CO2 and ruby laser annealing of ion-implanted Hg1−xCdx Te
Authors: Bahir G. , Kalish R.
Published: February 2003

The effects of cw CO2 and Q-switched ruby laser beam irradiation on donor (B, In) and acceptor (P) ion-implanted Hg1−xCdx Te (x = 0.2, 0.3) are reported. Rutherford backscattering and particle induced x-ray emission measurements for channeled and nonchanneled particles were used to investigate the crystal quality and its composition near the surface. It is shown that annealing by cw CO2 laser irradiation (120 W/cm2, 0.2 s) results in good crystal regrowth. Irradiation by light from pulsed ruby lasers (0.15 J/cm2, 50 ns) even though to a certain extent does anneal the damage, is accompanied by the dislodging of Hg atoms from the near-surface region. The present results thus explain our findings that electrical activation of donor and acceptor implants in HgCdTe can be achieved by cw CO2 laser annealing, but not by pulsed ruby laser irradiations.
Optical frequency domain reflectometry in single-mode fiber
Authors: Eickhoff W. , Ulrich R.
Published: February 2003

The backscattered light amplitude is measured from one end of a fiber as a function of optical frequency by tuning a HeNe laser over its linewidth. Fourier transform by a low-frequency electronic spectrum analyzer then reveals the spatial distribution of scattering and of the fiber losses.
Native grown plasma oxides and inversion layers on InGaAs
Authors: Tell B. , Nahory R. E. , Leheny R. F. , De Winter J. C.
Published: February 2003

Native plasma oxides which are water insoluble have been grown on both n- and p-type epilayers of In0.53Ga0.47As. For each case, capacitance-voltage measurements show that the surfaces can be varied from strong accumulation to strong inversion. The oxide resistivity is of order 1012 Ω cm, while the breakdown field is of order 106 V/cm.
Reduction of radiation induced soft error rates in devices utilizing localized state charge storage
Authors: Coon D. D. , Derkits G. E. , Shepard P. F.
Published: February 2003

It is shown that for semiconductor memory devices utilizing charge storage in localized states it is possible to achieve a high degree of immunity to soft errors. This is accomplished by the application of an electric field which is strong enough to efficiently remove carriers produced by radiation from the region where charge is stored in localized states but not so strong as to remove readily by field ionization charge already stored in localized states. Tests of this concept have been performed using energetic Compton electrons produced by gamma rays.
Organic conductors as electron beam resist materials
Authors: Tomkiewicz Y. , Engler E. M. , Kuptsis J. D. , Schad R. G. , Patel V. V. , Hatzakis M.
Published: February 2003

Conducting organic π-donor halide complexes such as tetrathiafulvalene bromide were discovered to act as electron beam resists, which display a unique combination of useful properties. Exposure of sublimed films to an electron beam generates the neutral π donor and the halogen which is subsequently lost from the film. Depending on exposure conditions, either negative (solvent developed) or positive (in-situ developed) resist images with a resolution of the order of 0.5 μ can be generated. The strongly absorbing (UV,vis.) and highly conducting (∼10/Ω cm) films were found to become transmitting and insulating upon electron beam irradiation.
Evaluation of the gas puff z pinch as an x-ray lithography and microscopy source
Authors: Bailey J. , Ettinger Y. , Fisher A. , Feder R.
Published: February 2003

Soft x rays (100–10 000 eV), due to their short wavelength (0.1–10 nm) can play an important role in high resolution microscopy and lithography. The gas puff Z pinch is an intense source of soft x rays. Calorimeter and x ray diode measurements showed that 10% of the stored electrical energy was converted to radiation in the range of 1–10 nm. Commercial photoresist polymethyl methacrylate (PMMA) and some new resists—CR 39, nitrocellulose, were exposed to the pinch radiation. The developed images on the resists have been studied with a scanning electron microscope. The resolution was found to be source limited, but a simple modification can improve the resolution by more than an order of magnitude.
Mechanism of open-circuit voltage enhancement in metal-insulator-semiconductor GaAs solar cells
Authors: Srivastava A. K. , Guha S. , Arora B. M.
Published: February 2003

Mechanism of open-circuit voltage enhancement in Au thin oxide-n-GaAs (1̄1̄1̄) solar cells prepared by room-temperature wet oxidation has been studied. In contrast to earlier published results on (100) GaAs, barrier heights for metal-insulator-semiconductor and metal-semiconductor cells are found to be the same, indicating absence of charge in the oxide or significant modification of surface states. It is shown that the increase in open-circuit voltage is mainly caused by suppression of the majority-carrier current due to tunneling through the oxide.
Ten-atmospheres high repetition rate rf-excited CO2 waveguide laser
Authors: Lo/vold S. , Wang G.
Published: February 2003

The design and operating characteristics of a pulsed, rf-excited CO2 waveguide laser operated at gas pressures up to 10 atm are reported. The results of small signal gain and gain decay time-constant measurements are also given.
Lattice defect structure of degraded InGaAsP-InP double-heterostructure lasers
Authors: Ishida K. , Kamejima T. , Matsumoto Y. , Endo K.
Published: February 2003

Lattice defect structure of degraded InGaAsP lasers has been investigated by scanning and transmission electron microscopy. It is found that although dislocation climb motion in InGaAsP lasers is slow, slip dislocations parallel to the stripe cause rapid degradation of the lasers.
A wavelength scannable XeCl oscillator—ring amplifier laser system
Authors: Pacala Thomas J. , McDermid I. Stuart , Laudenslager James B.
Published: February 2003

A holographic grating at grazing angle of incidence was used to achieve tunable, narrow bandwidth (0.005 nm) operation of a XeCl oscillator for injection locking of a ring amplifier. The amplifier’s narrow bandwidth output energy was constant and equal to the untuned, broadband output (∼15 mJ) in regions where injection locking was achieved. Scanning was provided by use of a stepping motor-driven differential micrometer on the tuning mirror. This system was used to produce a laser excitation spectrum of hydroxyl radicals (OH) in a flame.
Pulsed chemical laser with variable pulse-length electron-beam initiation and magnetic confinement
Authors: Amimoto S. T. , Whittier J. S. , Lundquist M. L. , Ronkowski F. G. , Hofland R. , Ortwerth P. J.
Published: February 2003

Performance of a pulsed HF/DF chain laser was investigated for the case of transverse initiation by a magnetically confined electron beam. Laser energy and beam quality are presented as functions of electron gun, magnetic field, gas mixture, and optical resonator parameters. The results include 79-J/l HF output and electrical efficiency for conversion of total incident e-beam energy to laser output energy of 45%.
Photoluminescence of pure GaAs crystals cleaved in ultrahigh vacuum
Authors: Fischer B. , Stolz H. J.
Published: February 2003

Photoluminescence measurements of pure GaAs crystals cleaved in ultrahigh vacuum (UHV) are compared to those of air-cleaved reference samples. Nonradiative surface recombination and band bending are considerably reduced at the UHV-cleaved surface. We find at low temperature (∼20 K) roughly the same spectral shape and the same integrated intensity for the UHV- and air-cleaved surfaces provided we apply a factor of 10 lower excitation power density to the UHV-cleaved surface. This factor of 10 stays constant over more than five orders of magnitude of excitation density. A detailed comparison of the spectra shows that the characteristic reabsorption minimum in the free-exciton polariton luminescence is missing in the case of the UHV-cleaved surface.
Self-annealed ion implanted n+-p diodes
Authors: Cembali G. , Finetti M. , Merli P. G. , Zignani F.
Published: February 2003

Self-annealing implantation with dopant ions has been successfully applied to the creation of n+-p silicon diodes. Experimental conditions as well as current voltage characteristics of self-annealed implanted diodes and thermally annealed diodes used as controls are presented.
Silicon molecular beam epitaxy on arsenic-implanted and laser-processed silicon
Authors: Smit L. , de Jong T. , Hoonhout D. , Saris F. W.
Published: February 2003

We report on the production of doped silicon layers buried under epitaxial undoped silicon layers, giving particular attention to the abruptness of the doped-undoped silicon interface. Arsenic-implanted silicon is both annealed and atomically cleaned using pulsed laser irradiation. Surface cleanliness and surface order are checked with Auger electron spectroscopy and low energy electron diffraction respectively. Molecular beam epitaxy is done with a substrate temperature between 300 and 600 °C, resulting in an epitaxial silicon layer of typically 100 nm. Rutherford backscattering plus channeling show that the arsenic concentration drops abruptly at the substrate-epitaxy interface and that the epitaxial layer is of good crystal quality.
High-frequency electro-optic oscillator using an integrated interferometer
Authors: Neyer A. , Voges E.
Published: February 2003

A hybrid electro-optic oscillator is built up with an integrated Mach–Zehnder interferometer on LiNbO3 and an electrical feedback circuit. Oscillation frequencies up to 1.54 GHz are achieved due to the high-frequency properties of the modulator. Oscillator operation as well as the synchronization behavior are analyzed by the describing function technique.
Two-dimensional electron gas in a In0.53Ga0.47As-InP heterojunction grown by metalorganic chemical vapor deposition
Authors: Guldner Y. , Vieren J. P. , Voisin P. , Voos M. , Razeghi M. , Poisson M. A.
Published: February 2003

We report, from Shubnikov-de Haas and cyclotron resonance experiments, the first observation of a two-dimensional, high-mobility electron gas in a selectively doped In0.53Ga0.47 As-InP heterojunction grown by metalorganic chemical vapor deposition. Several parameters of the electronic system under consideration are determined.
Epitaxy of CuI on Cu(111)
Authors: DiCenzo S. B. , Wertheim G. K. , Buchanan D. N. E.
Published: February 2003

Thin epitaxial films of CuI have been grown on clean Cu(111) surfaces by chemical reaction with iodine vapor. A lattice match is obtained because the iodine (111) planes of CuI have the same symmetry and approximately the same spacing as the (√3×√3)R30° iodine adsorbate layer which forms initially on exposure of clean Cu(111) to iodine vapor. This suggests that pairs of materials favorable for heteroepitaxy can consequently be identified by searching for agreement between submonolayer adsorbate structures and atom planes in solids.
Damage and lattice location studies of Si-implanted GaAs
Authors: Bhattacharya R. S. , Pronko P. P.
Published: February 2003

High-resolution Rutherford backscattering and proton-induced x-ray emission with channeling have been used to evaluate damage and lattice site location of Si-implanted GaAs. Semi-insulating Cr-doped GaAs (100) crystals were implanted at room temperature with 120-keV Si ions to a dose of 5×1015 cm−2. The residual damage and the locations in the lattice, which the implant occupies, are determined after annealing the samples at 950 °C for 15 min. It is shown that 70±7% of the implanted Si occupies substitutional lattice sites.
Tangential magnetoresistance of two-dimensional electron gas at a selectively doped n-GaAlAs/GaAs heterojunction interface grown by molecular beam epitaxy
Authors: Ohno H. , Sakaki H.
Published: February 2003

Magnetoresistance effect in a two-dimensional electron gas with high electron mobility (as high as 78 000 cm2/Vs at 77 K) at an n-GaAlAs/GaAs interface is reported for the magnetic field By, parallel to the interface. This tangential magnetoresistance is shown for the first time to contain a term having a linear dependence both on By and on electric field parallel to the current Ex, and is interpreted in terms of the scattering probability change due to the electron wave function deformation by Lorenz force. The polarity change of the linear term is shown to be the evidence for the one-sided distribution of ionized impurities.
Raman measurements of stress in silicon-on-sapphire device structures
Authors: Brueck S. R. J. , Tsaur B-Y. , Fan John C. C. , Murphy D. V. , Deutsch T. F. , Silversmith D. J.
Published: February 2003

Spatially resolved (∼1 μm) Raman scattering measurements of the Si optical phonon spectrum have been used to map the stress in silicon-on-sapphire device structures. Devices defined by an isolated island etch technique exhibit a stress relaxation extending about 1.5 μm from the edges of a 6-μm-wide Si stripe. Devices defined by a local oxidation of the Si exhibit a more uniform stress profile.
Disorder of an AlAs-GaAs superlattice by silicon implantation
Authors: Coleman J. J. , Dapkus P. D. , Kirkpatrick C. G. , Camras M. D. , Holonyak N.
Published: February 2003

Data are presented on a 126-layer AlAs-GaAs superlattice which has been selectively disordered by silicon implantation. Silicon ions, implanted at 375 keV and a dose of 1014 cm−2, yield a compositionally disordered region 0.33 μm thick centered 0.7 μm below the superlattice surface. The implanted region demonstrates reduced photoluminescence intensity relative to the unimplanted regions of the superlattice. The amphoteric nature of silicon and defect-induced vacancies account for the range and extent of disordering observed in the superlattice.
Tunable electro-optic waveguide TE〈–〉TM converter/wavelength filter
Authors: Alferness R. C. , Buhl L. L.
Published: February 2003

We report the first demonstation of electrical tuning of the center wavelength of waveguide electro-optic TE〈–〉TM converter/filters. Using a novel dual electrode configuration the filter center wavelength is shifted by one filter bandwidth by application of a 10-V tuning voltage.
The B→X transition in 200Hg 79Br
Authors: Tellinghuisen Joel , Ashmore J. Gail
Published: February 2003

The B→X spectrum of HgBr is photographed and analyzed for the single isotopic species 200Hg 79Br. The analysis confirms Wieland’s earlier analysis [Z. Elektrochem. 64, 761 (1960)] up to v″≃23 but is different for higher v″ levels, leading to a lower estimate of the ground-state dissociation energy, 𝒟e = 5500 cm−1. Franck–Condon calculations indicate that R′e−R″e = 0.57 A, which is somewhat greater than concluded in earlier work. The previously reported HgBr laser lines appear not to coincide with specific band heads in the spectrum; instead they probably involve a semicontinuous overlap of rotational lines in several v′-v″ bands of the 12 isotopic HgBr molecules of significance in ’’natural’’ HgBr.
Continuous electrowetting effect
Authors: Beni G. , Hackwood S. , Jackel J. L.
Published: February 2003

We introduce a new electrowetting effect, continuous electrowetting (CEW), and show its advantages for applications to displays and other electro-optic devices. We demonstrate experimentally, by using CEW, fast and reversible electrowetting flow on the theoretically predicted scale of ∼10 cm/s for ∼1-V driving voltage.
Theory of transverse charging of electrons into a magnetic mirror
Authors: Barak G. , Gilad P.
Published: February 2003

Inductive charging is a method to inject electrons perpendicular to a magnetic field and trap them by means of this fast rising field. The method has been studied experimentally in recent years and densities higher than 1011 cm−3 were reached. It has been suggested to use it for the collective focusing ion accelerator and for high current betatrons. We present here a theory of the trapping mechanism. This theory explains most of the experimental results. We also give the various limits on the charge which can be trapped and held in a single mirror and in a multiple-mirrored torus.
Redistribution of manganese after annealing of GaAs implanted with Si+ and Se+
Authors: Kanber H. , Feng M. , Whelan J. M.
Published: February 2003

The redistribution of Mn in Si+ and Se+ implanted Cr-doped semi-insulating GaAs substrates is studied by secondary-ion mass spectrometry as a function of implant dose, energy, and annealing temperature subsequent to annealing capless and with a SiO2 cap in a As4-H2 atmosphere. Mn accumulates within a depth of 0.5 μm from the GaAs surface with a peak at ∼500 Å from the surface for capless anneals. The Mn peak position is constant as the implant energy is varied. The role of the encapsulant in gettering Mn is described. The observed accumulation of Mn near the surface region of GaAs can cause p-type conversion of this region as reported by Klein. A higher solid solubility (≊ 3×1018 atoms/cm3) and a higher diffusion rate of Mn than of Cr in GaAs at 900 °C are indicated by the dose study. A preliminary model for the Mn diffusion mechanism under the above conditions is proposed.
Effect of heterojunction spike on the quantum efficiency of an AlGaAs/GaAs heterojunction charge coupled device
Authors: Liu Y. Z. , Anderson R. J. , Milano R. A. , Cohen Marshall J.
Published: February 2003

The ’’spike’’ in the conduction resulting from the band-gap discontinuity in a p- GaAs/n-Al0.3Ga0.7As heterojunction is observed via the blocking of photoexcited electron flow from the p-GaAs to the n-Al0.3Ga0.7As. The spike height deduced from photocurrent versus bias results is 0.14 eV above the conduction-band minimum of p-GaAs. This value is 0.13 eV lower than that predicted by theory and suggests a positive interface charge density of 4×1011 cm−2. The lowered barrier does not appear to reduce the electron collection in the charge coupled device operation under low light level illumination.
An accurate method to check chemical interfaces of epitaxial III-V compounds
Authors: Bisaro R. , Laurencin G. , Friederich A. , Razeghi M.
Published: February 2003

We have developed a method of chemical beveling coupled with line scan Auger measurements to check abrupt interfaces of epitaxial III-V compounds. Interface widths between 53 and 89 Å have been measured by this method for an InP/Ga0.47In0.53As/InP double heterostructure grown by low pressure metalorganic chemical vapor deposition. The ultimate width checkable by this method lies between 10 and 15 Å and is of the order of magnitude of the escape depth of the Auger electrons selected.
Large optical cavity AlGaAs buried heterostructure window lasers
Authors: Blauvelt H. , Margalit S. , Yariv A.
Published: February 2003

Large optical cavity buried heterostructure window lasers in which only the transparent AlGaAs waveguiding layers, and not the active layer, extend to the laser mirrors have been fabricated. These lasers have threshold currents and differential quantum efficiencies comparable to those of regular large optical cavity buried heterostructure lasers in which the active region extends to the laser mirrors, however the window lasers have been operated under pulsed conditions at three times the power at which otherwise identical lasers without windows degrade by catastrophic mirror damage.
Spectroscopic identification of Si donors in GaAs
Authors: Low T. S. , Stillman G. E. , Collins D. M. , Wolfe C. M. , Tiwari S. , Eastman L. F.
Published: February 2003

Photothermal ionization measurements on Si-doped GaAs grown by molecular beam epitaxy (MBE) have indicated that the previous identification of the Si donor peak was incorrect. Data leading to the new identification are presented and the results leading to the earlier identification are re-examined. Implications of the new identification for the importance of Si as a residual donor in epitaxial GaAs grown by various techniques are discussed.
Noncontact optoacoustic determination of gas flow velocity and temperature simultaneously
Authors: Zapka W. , Tam A. C.
Published: February 2003

We have developed a new noncontact optoacoustic method for simultaneous measurement of flow velocity and temperature in a flowing fluid to accuracies of 5 cm/s and 0.1 °C, respectively. It is applicable for pure particulate-free gases and liquids. A pulsed ND-doped yttrium aluminum garnet (YAG) laser of 40-mJ energy and 10-ns duration generates an acoustic pulse whose propagations in directions along and against the flow are monitored by a total of three cw probe beams. We also describe the minimization of errors due to a blast wave (which propagates faster than sound) being generated at the source.
Photoquenching of electroluminescence in ZnS:TbF3 thin films
Authors: Kobayashi Hiroshi , Tanaka Shosaku , Sasakura Hiroshi , Tsujita Kosaku , Tueta Roger
Published: February 2003

The photoquenching effect of electroluminescence (EL) has been observed for the first time in thin-film ZnS:TbF3 EL devices. The luminescent intensity and the conductive charge are quenched, when the device is exposed to a visible light of energy between 1.75–2.75 eV. The maximum photoquenching rate of 45% is observed at a voltage slightly higher than the EL threshold voltage. The recovering time from the photoquenching is of the order of several seconds. This photoquenching effect is likely to be due to deep hole traps.
An achromatic quadrupole lens doublet for positive ions
Authors: Martin F. W. , Goloskie R.
Published: February 2003

The resolution and chromatic aberration of a doublet of achromatic quadrupole lenses have been experimentally measured. Each achromatic lens is of length 5.99 cm and comprises an electric quadrupole of bore 1.05 mm and a magnetic quadrupole of bore 3.40 mm. In preliminary tests with 600-keV protons, a chromatic aberration coefficient of less than 1.2 cm and beam width of 4 μ are measured, compared to 20 cm and 4 μ for the same doublet operated in a solely magnetic mode.
CdI and CdBr photodissociation lasers at 655 and 811 nm: CdI spectrum identification and enhanced laser output with 114CdI2
Authors: Ediger M. N. , McCown A. W. , Eden J. G.
Published: February 2003

Lasing on the B→X bands of CdI at 655 nm and CdBr at 811 nm has been obtained by photodissociating CdI2 and CdBr2 with an ArF laser. Also, the CdX (X = I, Br) B-state radiative lifetimes and CdX2 quenching rate constants were found to be 32±3 ns, (9.2±1.1)×10−10 cm3 s−1, 25±4 ns and (7.9±3.3)×10−10 cm3 s−1, respectively. After synthesizing and photodissociating 114CdI2, the 114CdI laser spectrum was identified as arising from v′ = 0−2→v\ = 61, 62 transitions of the B→X band. The use of a single isotope of Cd (i.e., 114Cd) was also found to quadruple the energy output of the CdI laser and to make possible a dual-wavelength metal-halide laser, one operating simultaneously in the red (CdI) and near-infrared (CdBr).
Bistability and negative resistance in semiconductor lasers
Authors: Harder Ch. , Lau K. Y. , Yariv A.
Published: February 2003

Experimental results of a buried heterostructure laser with a segmented contact to achieve inhomogeneous gain are presented. Measurements reveal a negative differential resistance over the absorbing section. Depending on the source impedance of the dc current source driving the absorbing section, this negative resistance can lead to (i) bistability with a very large hysteresis in the light-current characteristic without self-pulsation or (ii) a small hysteresis with self-pulsations at microwave frequencies. An analysis, which includes the electrical part of the device, leads to an explanation of self-pulsations in inhomogeneously pumped lasers without having to rely on a sublinear gain dependence on injected carrier concentration.
Picosecond high power extraction from an unstable resonator based injection-locked XeCl laser
Authors: Varghese Thomas
Published: February 2003

Single pulse peak power of over 0.3 GW with good beam quality was obtained from an injection-locked XeCl laser based on a positive branch confocal unstable resonator. The high power thus obtained has the potential of generating efficient high power tunable picosecond pulses from organic dyes in the UV and near UV region of the spectrum by pumping in a synchronous scheme.
Resonant degenerate four-wave mixing in GaAs multiquantum well structures
Authors: Hegarty J. , Sturge M. D. , Gossard A. C. , Wiegmann W.
Published: February 2003

We have observed degenerate four-wave mixing, on a picosecond timescale, at the lowest two-dimensional exciton resonance line of GaAs-Al0.25Ga0.75As layer structures, grown by molecular beam epitaxy. Mixing is observed at exciton densities as low as 109 cm−2 per layer and is strongly resonant at the heavy exciton line, where the diffraction efficiency reaches a maximum of 12% for a 2×10−7 J/cm2 pump pulse.
Surface structure of epitaxial Pd2Si thin films
Authors: Oura Kenjiro , Okada Satoshi , Kishikawa Yozo , Hanawa Teruo
Published: February 2003

The surface structure of Pd2Si thin films epitaxially grown on clean Si (111) 7×7 surfaces has been studied by low-energy electron diffracton (LEED) and Auger electron spectroscopy (AES). Heat treatment in the range of 200–600 °C causes surface segregation of elementary Si over a Pd2Si (0001) surface and produces a reconstructed 3×3 superstructure of Pd2Si. A nonreconstructed Pd2Si-1×1 surface is produced after removing the segregated Si layer by Ar ion beams and its ordering is found to be not damaged by ion sputtering. A possible cause for the thermally induced Si segregation is also examined experimentally and discussed.
Generation of subpicosecond coherent optical pulses by passive mode locking of an AlGaAs diode laser
Authors: Yokoyama Hiroyuki , Ito Hiromasa , Inaba Humio
Published: February 2003

Subpicosecond coherent optical pulses as short as 0.58 ps were generated for the first time by passive mode locking of an AlGaAs double heterostructure diode laser. It was realized by a simple configuration made of a conventional AlGaAs diode laser without antireflection coatings on both facets, which was aged and exhibiting self-pulsation, placed in an external cavity. When the external cavity length was shorter than about 60 mm, almost complete mode locking was observed over the oscillation spectrum of 3.5 nm in width. Based on the second-harmonic generation autocorrelation measurement, ultrashort coherent optical pulses from 0.58 to 1.2 ps in duration were demonstrated by increasing the external cavity length together with the proper control of the optical feedback effect and the pumping dc current.
Degraded InGaAsP/InP double heterostructure laser observation with electron probe microanalyzer
Authors: Seki Masahiro , Fukuda Mitsuo , Wakita Koichi
Published: February 2003

Dark spots associated with degradation in InGaAsP/InP double heterostructure lasers were examined by electron probe microanalyzer, cathodoluminescence micrograph, and sequential selective etching procedures. It has been clarified that these dark spots penetrate from the p-cladding layer to the n-cladding layer and have no direct relation with InP substrate defects. Segregation of As and Ga in an active layer geometrically correlates with these dark spots. Dark spot generation and segregation were seen to develop with degradation induced in the laser operation.
Thermal oxidation of nickel disilicide
Authors: Bartur M. , Nicolet M-A.
Published: February 2003

The thermal oxidation characteristics of nickel disilicide on Si substrates have been investigated in the temperature range of 700–900 °C in dry oxygen and wet oxygen. A surface layer of SiO2 grows parabolically in time. The growth rate is independent on the crystalline structure (epitaxial or polycrystalline) and thickness of the NiSi2 layer. We surmise that the oxidation mechanism is dominated by oxygen diffusion through the growing SiO2. Activation energies for the dry and wet oxidation are 1.0±0.1 eV and 1.5±0.1 eV, respectively. NiSi2 layers on SiO2 oxidize with the same rate—resulting with progressively Ni-rich NiSi2. Preliminary measurements of the oxide quality yield dielectric strength of 2.1×106 V cm−1, and a pinhole density of about 100 per cm2. A survey of oxidation data for Si and other refractory metal silicides shows that their oxidation does not draw similar kinetics to that of NiSi2.
Compensating impurity effect on epitaxial regrowth rate of amorphized Si
Authors: Suni I. , Göltz G. , Grimaldi M. G. , Nicolet M-A. , Lau S. S.
Published: February 2003

The epitaxial regrowth of ion-implanted amorphous layers on 〈100〉 Si with partly compensated doping profiles of 11B, 75As, and 31P was studied. Single implants of these impurities are found to increase the regrowth rate at 475 and 500 °C. The compensated layers with equal concentrations of 11B and 31P or 11B and 75As show a strong decrease of the regrowth whereas for the layers with overlapping 75As and 31P profiles no compensation has been found.
External off and on switching of a bistable optical device
Authors: Tarng S. S. , Tai K. , Jewell J. L. , Gibbs H. M. , Gossard A. C. , McCall S. L. , Passner A. , Venkatesan T. N. C. , Wiegmann W.
Published: February 2003

A GaAs etalon has been switched on in a detector-limited time of 200 ps by a 10-ps, 600-nm, 1-nJ pulse and switched off in ⩽20 ns by a 7-ns, 600-nm, 300-nJ pulse.
Experimental investigation of the infrared absorption saturation in p-type germanium and silicon
Authors: James R. B. , Schweig Edgard , Smith D. L. , McGill T. C.
Published: February 2003

We investigate the room-temperature absorption saturation of p-Ge and p-Si for several samples over a range of doping densities for light having wavelengths of 10.6 and 9.6 μm. The transmission data can be fairly well described using an intensity dependent absorption coefficient characteristic of an inhomogeneously broadened two-level system. Measurements of the saturation intensity of p-Ge show that Is increases monotonically with increasing hole concentration, and that the resonant transition is significantly easier to saturate in p-Ge than in p-Si for the samples we examined.
First and second order twin boundaries in edge defined film growth silicon ribbon
Authors: Cunningham B. , Strunk H. , Ast D. G.
Published: February 2003

The equilibrium defect structure of edge defined film-fed growth ribbons consists of linear twins and twin bundles lying parallel to the growth direction. These twins show similar etching behavior in spite of the fact that their electrical activity i.e. efficiency as recombination centers, can vary greatly. Correlated electron beam induced current microscopy and high voltage transmission electron microscopy show (i) that some of the linear boundaries consist of alternating sections of coherent first order twins and incoherent second order twins of the {111}/{115} type and (ii) that the first order twins are not electrically active, whereas the second order twins act as strong recombination centers. Structural models of the {111}/{115} interface indicate a large fraction of dangling bonds. Macroscopically, the alternating sections of these twin boundaries form single straight boundaries running parallel to the growth direction of the ribbon. In etching experiments the alternating sections of boundaries described above are therefore difficult to differentiate from coherent first order twins.
Investigation on TiSi2 thin-film oxidation by radioactive tracer technique
Authors: Chen Jiann-Ruey , Liu Yuen-Chung , Chu Sheng-Deh
Published: February 2003

The tracer technique using radioactive 31Si (T1/2 = 2.62h) was performed to study the oxidation kinetics of TiSi2 thin films on single and polycrystalline silicon. After depositing 1000-Å 31Si which had been activated in a nuclear reactor, radioactive TiSi*2 was formed by coating 500-Å Ti film in situ and then annealing at 850 °C for 45 min. On wet oxidation, the substrate silicon atoms transported through the TiSi*2 layer by grain boundary and/or interstitial diffusion. These results were confirmed by Geiger counting after etching the outer SiO2 layer step by step.
Fiber optic laser probe for acoustic wave measurements
Authors: Jungerman R. L. , Bowers J. E. , Green J. B. , Kino G. S.
Published: February 2003

An optical probe has been developed for acoustic surface waves using single-mode fiber to illuminate the sample. The scanned fiber probe has an effective spot size of 4 μm without the use of focusing lenses. 34% of the incident light re-enters the fiber from a specular reflector. The signal from the sample is combined with a reference in a single fiber, eliminating misalignment in the interferometric measurement. Experimental results are presented for a LiNbO3 focused transducer surface acoustic wave (SAW) device. On this device, the probe exhibits 60-dB dynamic range and 3×10−2 Å minimum sensitivity. The resolution, sensitivity, and flexibility of the fiber probe make it applicable to crack detection in nondestructive testing.
Growth of single-crystal silicon islands on bulk fused silica by CO2 laser annealing
Authors: Hawkins W. G. , Black J. G. , Griffiths C. H.
Published: February 2003

A CO2 laser beam focused to 50 μm was used to heat bulk fused silica which had previously defined Si3N4 encapsulated chemical vapor deposited polycrystalline silicon islands (25×100 μm) on its surface. It was easily possible to melt the silicon and force recrystallization without damaging the fused silica substrate. The recrystallization process produces single-crystal islands under a wide variety of laser treatment parameters. Under certain conditions, the recrystallized islands exhibit a (100) plane parallel to the substrate. These results are the first demonstration of oriented single-crystal thin-film growth using island predefinition, which eliminates thermal stress induced microcracking resulting from the mismatch in expansion between silicon and bulk fused silica.
AlGaAs lasers with micro-cleaved mirrors suitable for monolithic integration
Authors: Blauvelt H. , Bar-Chaim N. , Fekete D. , Margalit S. , Yariv A.
Published: February 2003

A technique has been developed for cleaving the mirrors of AlGaAs lasers without cleaving the substrate. Micro-cleaving involves cleaving a suspended heterostructure cantilever by ultrasonic vibrations. Lasers with microcleaved mirrors have threshold currents and quantum efficiencies identical to those of similar devices with conventionally cleaved mirrors.
Near-infrared picosecond pulse generation in a cw mode-locked dye laser pumped directly by an argon ion laser
Authors: Jain R. K.
Published: February 2003

We describe the efficient generation of wavelength-tunable picosecond pulses in the deep red and near-infrared spectral regions (∼6000–8000 Å) in a synchronously mode-locked cw dye laser that is pumped directly by 5145-Å radiation from an argon ion laser. Operation of the dye laser in the near infrared was achieved with the use of an excitation transfer mixture of commercial laser dyes. With 1 W of average pump power, an average output power of 70 mW was obtained at the peak of the tuning curve.
Electron beam pumped cw Hg ion laser
Authors: Rocca J. J. , Meyer J. D. , Collins G. J.
Published: February 2003

We have obtained cw laser action using electron beam excitation of a He-Hg mixture. This represents a new method of exciting cw lasers and offers the possibility of increased efficiency for ion lasers.
Diffusivity of oxygen in silicon during steam oxidation
Authors: Mikkelsen J. C.
Published: February 2003

The diffusivity of oxygen in silicon during steam oxidation at 700–1240 °C was measured on as-oxidized Si wafers. To provide greater analytical sensitivity 18O was introduced into the float-zone Si wafers from 1-atm H2 18O steam, and the 18O depth profiles were measured by Cs+ secondary ion mass spectrometry. Over the entire temperature range studied, the diffusivity is governed by a single activation energy, 2.44 eV, and the prefactor is 7×10−2 cm2 s−1. Our results are compared with previous literature values measured only at high temperature.
Shallow N acceptor in N+-implanted ZnSe
Authors: Wu Z. L. , Merz J. L. , Werkhoven C. J. , Fitzpatrick B. J. , Bhargava R. N.
Published: February 2003

A new bound exciton line IN1 at 2.7916 eV and its longitudinal phonon replicas have been observed in N+-ion-implanted ZnSe. Compared with the data of unimplanted samples, the pair bands are more intense and shift towards high energy by about 13 meV. These results provide confirmation that nitrogen is incorporated into ZnSe as a shallow acceptor.
Optical probing technique for inhomogeneous superconducting films
Authors: Chi C. C. , Loy M. M. T. , Cronemeyer D. C.
Published: February 2003

We report a nondestructive optical probing technique for superconducting films, by which a cross-sectional gradient of the local transition temperature Tc and a two-dimensional map of the local critical current Ic of an Al film were obtained. The two-dimensional map clearly shows a variety of defects of the Al film. Some of them can be correlated to visible pinholes.
The hydrodynamics of liquid metal ion sources
Authors: Wagner A.
Published: February 2003

Factors affecting the current-voltage characteristics of liquid metal ion sources are reviewed. The results demonstrate that ion emission is not controlled by space-charge effects but rather is determined by liquid flow limitations along the needle emitter. A hydrodynamic model is presented which predicts the experimental I-V characteristics. The model suggests that a reduction in the energy spread (Boersch Effect) of the emitted ions may be achieved by increasing the needle flow impedance.
Localized laser etching of compound semiconductors in aqueous solution
Authors: Osgood R. M. , Sanchez-Rubio A. , Ehrlich D. J. , Daneu V.
Published: February 2003

A laser-based technique for rapid, anisotropic etching of compound semiconductors is described. Both holes for through-wafer vias and high-resolution diffraction gratings have been made with the process.
Recrystallization of Si on amorphous substrates by doughnut-shaped cw Ar laser beam
Authors: Kawamura S. , Sakurai J. , Nakano M. , Takagi M.
Published: February 2003

Continuous single-crystal Si films longer than 600 μm over SiO2 have been produced with or without lateral epitaxial growth from bulk silicon seed by changing the mode structure of the cw Ar laser beam. The thermal profile of the laser spot is controlled by using a doughnut-shaped beam instead of usual Gaussian one to suppress competitive nucleation from side edges of the molten zone. The result indicates that the liquid-solid interface line profile is the most essential limiting parameter on the mechanism of regrowth.
Very low resistance ohmic contacts on p-type InP by direct plating
Authors: Tabatabaie-Alavi K. , Choudhury A. N. M. M. , Slater N. J. , Fonstad C. G.
Published: February 2003

Very low resistance ohmic contacts (ρc ≃4×10−5 Ω cm2) have been formed on p-type InP by light assisted plating of Au and Zn. The plating technique, which uses alternating positive and negative current pulses, is suitable for producing patterned, small care contacts on device structures and is compatible with established n-type ohmic contacting procedures.
Quasi-Schottky barrier diode on n-Ga0.47In0.53As using a fully depleted p+-Ga0.47In0.53As layer grown by molecular beam epitaxy
Authors: Chen C. Y. , Cho A. Y. , Cheng K. Y. , Garbinski P. A.
Published: February 2003

A quasi-Schottky barrier diode made on n-Ga0.47In0.53 As has been demonstrated. This device utilizes a fully depleted ultrathin p+-Ga0.47In0.53 As layer grown by molecular beam epitaxy to increase the barrier height. An increase in the barrier height of 0.27 V, making the total barrier height 0.47 V, has been obtained. A low reverse leakage current and a hysteresis-free capacitance-voltage characteristic suggest that this structure should be useful as a current control gate for high speed field-effect transistors.
Collection length of holes in a-Si:H by surface photovoltage using a liquid Schottky barrier
Authors: Moore Arnold R.
Published: February 2003

In a surface photovoltage determination of the collection length of holes in undoped amorphous Si:H, the ac surface photovoltage has been picked up by the use of a liquid Schottky barrier. The redox couple quinone-hydroquinone proved the best liquid. Simultaneous illumination with a bias light of up to 1 sun removes most of the internal barrier field allowing measurement of the ambipolar diffusion length. Values in the range 0.01–0.8 μm are found depending on the conditions of sample preparation.
Photocurrent onset potential and flatband potential of a p-type GaP semiconducting photoelectrode
Authors: Horowitz G.
Published: February 2003

A discrepancy between the photocurrent onset potential and the flatband potential derived from capacitance voltage measurements has been observed on p-type GaP semiconducting photoelectrodes. This discrepancy has been attributed previously by Butler and Ginley to a localized state acting as a recombination center. It is demonstrated that the experimental current-voltage characteristic can be fitted to a curve calculated from a theoretical model that takes into account the rate limitation due to the charge transfer across the semiconductor-electrolyte interface, and the recombinations in the space-charge layer. The very low electron and hole transfer currents across the interface are attributed to the weak overlap between semiconductor bands and redox ion state densities.
Tunneling in the reverse dark current of GaAlAsSb avalanche photodiodes
Authors: Tabatabaie N. , Stillman G. E. , Chin R. , Dapkus P. D.
Published: February 2003

The reverse dark current of Ga0.8Al0.2AsySb1−y avalanche photodiodes was measured over a wide temperature range. The dark current at high voltages is dominated by a tunneling component which has been identified as defect tunneling because the tunneling energy is considerably less than the band-gap energy. This identification is supported by the observation of a second tunneling component which becomes dominant at high electric fields.
Conversion of the conductivity mode in silicon by oxygen ion implantation and its application in a novel dielectric isolation technique
Authors: Chi J. Y. , Holmstrom R. P. , Mao B. Y.
Published: February 2003

Implanted oxygen ions have been shown to form donor states and to change the conductivity mode in large regions of p-type single-crystal silicon after a 2-h 450 °C anneal. These donor states are annihilated by a brief high-temperature anneal. With a conventional oxide mask, this phenomenon has been used for the selective formation of low carrier concentration p-type regions dielectrically isolated from a p-type substrate by the full isolation by porous oxidized silicon technique.
Electron trapping in SiO2—An injection mode dependent phenomenon
Authors: Eitan B. , Frohman-Bentchkowsky D. , Shappir J. , Balog M.
Published: February 2003

Electron trapping in metal-oxide-silicon structures and its dependence on the injected electron energy distribution and oxide field were studied. It is found that at high injection levels trapping efficiency and saturation level increase with the accelerating field in the Si, and decrease with increase in the oxide field. These results differ markedly from those obtained in low level injection, in which it is assumed that trapping is of electrons injected from the Si into the oxide conduction band. Based on the high level injection experimental results, it is proposed that significant electron trapping is obtained through direct tunneling of hot electrons with energy less than the potential barrier, into localized states in the oxide near the Si-SiO2 interface.
Multiplication noise in planar InP/InGaAsP heterostructure avalanche photodiodes
Authors: Shirai Tatsunori , Yamasaki Susumu , Osaka Fukunobu , Nakajima Kazuo , Kaneda Takao
Published: February 2003

Planar InP/InGaAsP avalanche photodiodes have been fabricated and multiplication noise is discussed. The effective hole to electron ionization rate ratio is found to be 1.9 from the wavelength dependence of multiplication noise.
Magnetic field assisted alignment of nematic liquid crystal on a polymeric surface
Authors: Koshida Nobuyoshi , Kikui Sueo
Published: February 2003

The properties of magnetic field assisted alignment of nematic liquid crystal (LC) are described. Nearly perfect homogeneous alignment is obtained with the aid of an external magnetic field along the substrates. It is shown that there exist anisotropic interactions between LC molecules and a simply dip-coated polymeric surface and that interfacial forces enhanced by an appropriately directed field can establish a stable alignment. The possibility of this alignment technique as an alternative to rubbing is also examined.
Electron tunneling through GaAs grain boundaries
Authors: Seager C. H. , Pike G. E.
Published: February 2003

Measurements of the zero-bias dc conductance G0 and high frequency capacitance have been made on GaAs bicrystals doped in the range of 4×1017–2×1018 cm−3. The conductance displays a non-Arrhenius temperature dependence with high temperature values of ∂(ln G0)/∂(1/kT) less than the barrier heights deduced from the capacitance. Theoretical calculations of transbarrier currents using the unified approach of Fonash show that thermally assisted tunneling currents are important.
Coherent oscillation by self-induced gratings in the photorefractive crystal BaTiO3
Authors: White Jeffrey O. , Cronin-Golomb Mark , Fischer Baruch , Yariv Amnon
Published: February 2003

We report here the demonstration of several new optical oscillator configurations including a unidirectional ring oscillator and a self-pumped phase conjugate mirror. The gain medium is BaTiO3, pumped by a 632.8-nm He-Ne laser at power levels down to 50 μW.
Effect of superluminescence on the modulation response of semiconductor lasers
Authors: Lau Kam Y. , Yariv Amnon
Published: February 2003

The small-signal modulation response of semiconductor lasers with a very small mirror reflectivity is analyzed. Superluminescent effects inside the laser cavity provide yet another mechanism for damping relaxation oscillation resonance. These results can serve as useful guides in designing high frequency semiconductor lasers.
Bragg condition in absorbing x-ray multilayers
Authors: Rosenbluth Alan E. , Lee Ping
Published: February 2003

The angle of maximum reflectivity from a multilayer x-ray reflector is influenced by absorption in the medium. Using multilayer theory we show how the full refractive correction compares to the usual correction that includes only the effect of dispersion. The physical significance of the two corrections is discussed. The absorption correction is computed for some multilayer systems of current interest.