bluuebunny/crossref_metadata_2025 huggingface dataset:
I-V and C-V characteristics of Cr∥H-Pc∥ Cr organic sandwich cell
Authors: Isett L. C.
Published: February 2003

The measurement of the capacitance of a thin-film organic semiconductor sandwich by the capacitor discharge technique and by the quasistatic technique is considered. It is suggested that the apparent voltage dependence of the capacitance is due to charge injection and transport and is not directly related to barrier formation. Data obtained on Cr ∥ phthalocyanine ∥ Cr sandwiches are in good agreement with this model.
Hall mobility of polycrystalline silicon
Authors: Maruska H. Paul , Ghosh Amal K. , Rose Albert , Feng Tom
Published: February 2003

Hall mobility of polycrystalline silicon was measured in the dark and under illuminated conditions. Grain boundary potential barriers present in the dark can be eliminated with light. When the barriers are removed, the mobility between 200 and 400 K is found to vary as T−2, which is the dependence observed in single crystals for the same order of magnitude of doping. The free-carrier concentration of 5×1015 cm−3 was not affected by illumination, and the room temperature mobility in 1-mm grain size material after barrier elimination with light was 900 cm2/V sec. A phenomological theory of Hall mobility in polycrystallllne silicon which explains these observations is presented.
Direct synchrotron x-ray topography of moving domain walls in Fe : Si single crystals
Authors: Hartmann W. , Hagen W. , Miltat J.
Published: February 2003

A real-time x-ray topography study of moving magnetic domain walls in an Fe : Si single crystal has been performed with double-crystal setting at the synchrotron radiation laboratory LURE. The domain walls were driven by a low-frequency magnetic field and viewed directly by means of a television detector system. Wall locking as well as wall bowing, the latter implying charged walls, have been observed.
Infrared surface wave interferometry
Authors: Schlesinger Z. , Sievers A. J.
Published: February 2003

An interference phenomena is described which involves infrared surface electromagnetic waves on coated metals. The interference is demonstrated with a two-beam surface wave interferometer of variable path length which utilizes the strong coupling between surface and bulk electromagnetic waves at coating edges.
Exact cavity equations for lasers with large output coupling
Authors: Siegman A. E.
Published: February 2003

The author shows how to write an exact cavity-mode expansion and obtains formally simple yet exact equations of motion for real laser cavities with large output coupling and/or diffraction losses, using the actual transverse eigenmodes of the cavity as a basis set, and including fast transient variations, externally injected signals, and spontaneous emission noise.
Stress-relieved regrowth of silicon on sapphire by laser annealing
Authors: Sai-Halasz G. A. , Fang F. F. , Sedgwick T. O. , Segmuller Armin
Published: February 2003

We report on an annealing process which controls the stress in SOS. By laser power inputs of various durations, we regrow the Si on a compressed sapphire surface. The room temperature stress in Si correlates with the time scale of the annealing process. The effect can be understood in terms of thermal stress at the sapphire surface.
Polymer-modified electrodes: a new class of electrochromic materials
Authors: Kaufman Frank B. , Schroeder Albert H. , Engler Edward M. , Patel Vishnu V.
Published: February 2003

A new class of organic polymeric thin-film electrochromic materials is described. We show that the new polymer-modified electrodes change color reversibly in permanent thin-film form without the electrodeposition characteristics of organic liquid state systems such as the viologens. The polymer films exhibit good switching speeds (τ⩽100 ms), possess intrinsic memory, and show no chemical degradation or adhesion loss in preliminary life tests (104 cycles). It is demonstrated that several important electrochromic parameters can be varied by chemical modification of the polymeric material.
A triatomic Xe2Cl excimer laser in the visible
Authors: Tittel F. K. , Wilson W. L. , Stickel R. E. , Marowsky G. , Ernst W. E.
Published: February 2003

A new triatomic rare-gas halide laser using the molecular exciplex Xe2Cl is described. Laser emission centered at 518 nm with a special bandwidth of 30 nm and peak power of about 2 kW was obtained from an electron-beam-excited high-density Ar/Xe/CCl4 mixture.
cw multiwavelength transverse-junction-stripe lasers grown by molecular beam epitaxy operating predominantly in single-longitudinal modes
Authors: Tsang W. T.
Published: February 2003

A new multiwavelength transverse-junction-stripe (MW-TJS) laser is developed and demonstrated. Such MW-TJS laser is capable of emitting multiple predominantly single–longitudinal mode emissions having preselected lasing wavelengths. The wavelengths of the lasing lines, their separations, and the number of lasing lines obtainable from a single MW-TJS laser can be predetermined. In this experiment, the MW-TJS lasers were grown by molecular beam epitaxy (MBE). As an example, four different lasing lines at 9025, 8793, 8532 and 8276 Å were obtained simultaneously from a single 4-wavelength TJS laser. The pulsed and cw current thresholds Ith for such 4-wavelength TJS laser with cavity length of 375 μm and each active layer thickness of 0.5 μm are 245 and 252 mA, respectively. In the case of regular TJS lasers grown by MBE, the pulsed and cw Ith’s are 37–50 and 40–54 mA, respectively.
Ellipsometric study of annealing processes of phosphorus-ion-implanted layers of Si
Authors: Watanabe K. , Motooka T. , Hashimoto N. , Tokuyama T.
Published: February 2003

The annealing processes of high-dose P+-ion-implanted Si are studied by ellipsometry. The change in ellipsometric angle (Δ, ψ) during isothermal annealing is measured and compared with that of values calculated using a simple epitaxial regrowth model based on the distribution of the optical constants. The discrepancy between the experimental and the calculated change in angle shows imperfectness of annealing in the 500–550 °C temperature range.
Pulsed electron beam irradiation of ion-implanted copper single crystals
Authors: Hirvonen J. K. , Poate J. M. , Greenwald A. , Little R.
Published: February 2003

The effect of an intense, pulsed electron beam on high-dose implanted Cu single crystals has been studied. Rutherford backscattering and channeling have been used to obtain the depth concentration profiles and lattice locations of the implanted species (Au, Ag, and Ta) before and after pulsed electron beam irradiation. Channeling and secondary electron microscopy measurements show that the Cu surface melts during pulsed irradiation followed by an epitaxial lattice growth resulting in (i) a redistribution of the implanted species, (ii) some species (e.g., Au and Ag) remaining on lattice sites, and (iii) Ta leaving substitutional sites.
An n+-n-p germanium avalanche photodiode
Authors: Kaneda T. , Kagawa S. , Mikawa T. , Toyama Y. , Ando H.
Published: February 2003

Low-noise germanium avalanche photodiodes of an n+-n-p structure have been investigated. Deep n+-n-p junctions have a lower noise than shallow n+-p junctions because holes have a higher ionization coefficient in germanium, and these n+-n-p diodes have a higher hole-to-electron collection efficiency. An excess noise factor F≈7 at the multiplication factor of 10 are obtained at a wavelength of 1.3 μm, whereas F≈10 for n+-p diodes. An internal quantum efficiency of 70–80% is obtained at 1.3 μm.
The current-voltage characteristics of semiconductor-electrolyte junction photovoltaic cells
Authors: Reichman J.
Published: February 2003

Equations are derived giving the current-voltage characteristics of photovoltaic cells based on the semiconductor-electrolyte junction. Recombinations in the neutral region and space-charge region are included. It is shown that the rate-limiting effect of charge transfer across the interface enhances the recombination rate in these regions with increasing voltage, thereby reducing the fill factor. Significant differences in the behavior of these cells and other photovoltaic cells are pointed out.
A pulsed vapor source for use in ion sources for heavy-ion accelerators
Authors: Shiloh J. , Chupp W. , Faltens A. , Keefe D. , Kim C. , Rosenblum S. , Tiefenback M.
Published: February 2003

A pulsed cesium vapor source for use in ion sources for high-current heavy-ion accelerators is described. The source employs a vacuum spark in Cs and its properties are measured with a hot-filament Cs detector.
Correlation of the structure and electrical properties of ion-implanted and laser-annealed silicon
Authors: Cullis A. G. , Webber H. C. , Chew N. G.
Published: February 2003

Both transmission electron microscopy and four-point probe measurements have been used to compare the structure and electrical properties of As+- and P+-ion-implanted and Q-switched laser-annealed Si. Use of a uniform laser beam permitted accurate correlations to be made. It was found that the thickness of the initial amorphous surface layer controlled the radiation energy densities required for annealing onset and completion. Annealing onset variations were probably due to changes in the coupling of the radiation with the ion-damaged region. The variation in depth distribution of residual defects with changes in annealing conditions has been determined and shown often to produce a two-stage annealing characteristic. The effect of such defects on annealed-layer electrical properties has been determined. The presence of very-small-scale undulations on annealed surfaces is thought to be due to the propagation of shock waves through the annealed region.
Crystal structure and thermal oxidation of laser-recrystallized polycrystalline silicon
Authors: Kamins T. I. , Lee K. F. , Gibbons J. F..
Published: February 2003

Laser-recrystallized polycrystalline silicon exhibits a weak 〈111〉 preferred orientation, in contrast to the strong 〈110〉 texture seen in fine-grain poly-silicon. The oxide thickness thermally grown on laser-recrystallized poly-silicon is much greater than that on fine–grain poly-silicon when both are heavily phosphorus doped but is approximately the same when both films are lightly doped.
Generation and detection of unipolar stress pulses
Authors: Yu F. , Ilić D. B. , Khuri-Yakub B. T. , Kino G. S.
Published: February 2003

We have used pulse shaping of the applied voltages, varying the acoustic and the electrical impedances of our transmitters and receivers, and special transducer designs in our efforts to generate and detect unipolar stress pulses. Heavily damped broadband commercial transducers have been used, as well as a specially made thick air-backed PZT (lead zirconium titanate) plate and two different reflection mode transmitter-receiver configurations. A simple theory for transmitting and receiving transducers is presented which explains well a variety of different observations.
LiNbO3 coupled-waveguided TE/TM mode splitter
Authors: Mikami Osamu
Published: February 2003

A novel optical TE/TM mode splitter was fabricated using Ti-diffused LiNbO3 coupled waveguides. This splitter can spatially separate the TE and TM mode components and is compatible with single-mode fiber systems. Crosstalk less than −20 dB was realized at 1.15-μm wavelength. Optical insertion loss was 1.7 dB.
XeF(C) state lifetime and quenching by rare gases and fluorine donors
Authors: Waynant R. W.
Published: February 2003

The lifetime and quenching rate constants for the XeF(C) state have been measured when that state is produced by flash photolysis of XeF2 in the presence of such quenching gases as He, Ne, N2, Xe, Ar, XeF2, NF3, and F2. The lifetime measured in this manner is 957 ns and the quenching rate constants are 1.2×10−13, 3×10−13, 4×10−13, 1×10−12, 9×10−14, 1.7×10−10, 1.6×10−11, and 8×10−11 cm3 sec−1, respectively.
cw monoenergetic Cs+ ion source by photoionization
Authors: Dreyfus R. W.
Published: February 2003

Sequential absorption of two photons converts a Cs atomic beam into an ion beam with minimal change in the original thermal energy of the atoms. The random ion energy is measured to be <0.15 eV; consequently this ion beam is one of the ’’coldest’’ ion sources to date. Currently, the source brightness is 10−4 A/cm2 sr eV and appears extendible to ∼5 A/cm2 sr eV.
Lithium iodate, intracavity upconversion
Authors: See Y. C. , Falk Joel
Published: February 2003

We report cw intracavity upconversion using a lithium iodate crystal and an argon laser. A noise equivalent power of 5×10−14 W/Hz1/2 at 3.4 μm is reported. Noise properties of the upconverter were measured and are described herein.
Time dependence of the reflectivity of Si at 633 and 488 nm during pulsed laser annealing
Authors: Nathan Marshall I. , Hodgson R. T. , Yoffa Ellen J.
Published: February 2003

The time dependence of the optical reflectivity of Si during pulsed laser annealing at 530 nm has been measured at probe wavelengths 633 and 488 nm. Within experimental error, no difference between the durations of the reflectivity rise at the two wavelengths is observed. This behavior is inconsistent with the assumption that the rise in reflectivity results from a dense electron-hole plasma but is consistent with melting of the Si surface.
Mode-stabilized separated multiclad layer stripe geometry GaAlAs double heterostructure laser
Authors: Ishikawa H. , Takagi N. , Ohsaka S. , Hanamitsu K. , Fujiwara T. , Takusagawa M.
Published: February 2003

A new stripe geometry GaAlAs double heterostructure laser with built-in optical waveguide to stabilize the transverse mode parallel to the junction plane is developed. A novel optical waveguide and internal current confinement structure are realized in the structure. Lasers with strip width 4.7 μm and cavity length 200 μm showed cw threshold currents of 45–70 mA and highly stable transverse and longitudinal single-mode lasing.
Laser-induced microscopic etching of GaAs and InP
Authors: Ehrlich D. J. , Osgood R. M. , Deutsch T. F.
Published: February 2003

Ultraviolet laser photolysis of methyl-halides has been used to produce localized photoetching of GaAs and InP. A spatial resolution of ≃1μm has been achieved and an etch rate ≳104 times that of the dark reaction demonstrated. A chemical mechanism is proposed and the observed resolution is explained by a simple physical model.
Pressure-induced metallic and superconducting state of GaSe
Authors: Dunn K. J. , Bundy F. P.
Published: February 2003

Using a sintered-diamond-tipped opposed anvil apparatus and a cryogenic clamp press, the electrical resistance behavior of GaSe was investigated. It is found that GaSe becomes metallic for pressures over 250 kbar and superconducting at temperatures around 5 K. The superconducting transition temperature is not very sensitive to the applied pressure: dTc/dP is approximately −0.0018 K/kbar in the pressure range 250–400 kbar.
Angular and velocity distribution of desorbed sodium atoms
Authors: Grischkowsky D.
Published: February 2003

By means of a tunable dye laser and a long cylindrical absorption cell, the Knudsen Cosine Law was verified for the desorption of Na atoms from a glass surface. At the same time, the atoms were shown to have a Maxwellian velocity distribution. The overall velocity resolution exceeds that of previous measurements.
Narrow double-current-confinement channeled-substrate planar laser fabricated by double etching technique
Authors: Chen Chung-Yih , Wang Shyh
Published: February 2003

The double-current-confinement channeled-substrate planar (DCC-CSP) laser, fabricated by the newly developed double etching technique, with channel width smaller than carrier diffusion length is demonstrated. In the majority of the 2-μm DCC-CSP lasers tested, linear light-current relation and stable fundamental-mode operation have been uniformly observed over the range of current tested (up to 3–5Jth). The lasers operate in single longitudinal mode with fixed emission wavelength up to 2.2Jth. The narrow-channel DCC structure offers a method to relax the stringent design tolerance in the conventional CSP laser.
Field-assisted photoemission to 2.1 microns from a Ag/p-In0.77Ga0.23As photocathode
Authors: Gregory P. E. , Escher J. S. , Saxena R. R. , Hyder S. B.
Published: February 2003

Reflection-mode photoemission to a 2.1-μm threshold has been achieved from an externally biased Ag/p-In0.77Ga0.23As cathode. Quantum yield at 1.9 μm is 2×10−3 electrons per incident photon for 2.4-V bias and a cathode cooled to ∼125 K. The cathode was grown by vapor-phase epitaxy on a compositionally graded InAsP on InP (100) substrate using the hydride process.
Low-temperature growth of piezoelectric AlN film by rf reactive planar magnetron sputtering
Authors: Shiosaki T. , Yamamoto T. , Oda T. , Kawabata A.
Published: February 2003

A single-crystalline aluminum nitride film is grown on a basal-plane sapphire substrate and the c-axis-oriented films are grown on glass and gold-film substrates at substrate temperatures as low as from 50 to 500 °C by using reactive rf planar magnetron sputtering. Surface acoustic waves are generated in both structures where interdigital transducers are located on the top of an aluminum nitride film and at the interface between the film and the substrate sapphire. The effective surface acoustic wave coupling factor k2 is 0.09 and 0.12%, respectively, for these interdigital transducer configurations. The aluminum nitride films sputtered on a gold film on a glass rod and on a glass sheet itself are also piezoelectric and used as bulk and surface acoustic wave transducers, respectively. These piezoelectric aluminum nitride films on glass and metal-film substrates have become available for the first time because film growth at low temperature has become possible in the present study.
Hydrogen passivation of point defects in silicon
Authors: Benton J. L. , Doherty C. J. , Ferris S. D. , Flamm D. L. , Kimerling L. C. , Leamy H. J.
Published: February 2003

Laser melting of crystalline silicon introduces electrically active defects which are observed by capacitance transient spectroscopy. The electrical activity of these point defects is neutralized by reaction with atomic hydrogen at 200 °C.
Optical injection locking of Si IMPATT oscillators
Authors: Yen H. W.
Published: February 2003

An experimental study on optical injection locking of X-band silicon IMPATT oscillators was carried out. The locking process was achieved by modulating a cw GaAlAs laser at subharmonics of the IMPATT oscillation frequency and optically injected into the IMPATT diode. A locking range of several megahertz can be obtained at frequency ratios ranging from 4:1 to 8:1.
GaAs-AlxGa1−xAs buried-heterostructure lasers grown by molecular beam epitaxy with Al0.65Ga0.35As (Ge-doped) liquid phase epitaxy overgrown layer for current injection confinement
Authors: Tsang W. T. , Logan R. A.
Published: February 2003

GaAs-AlxGa1−xAs buried-heterostructure (BH) lasers were fabricated by a molecular beam epitaxy/liquid phase epitaxy (MBE/LPE) hybrid technique. The BH lasers with 5 μm stripe width have cw current thresholds as low as 15 and 26 mA for diode lengths of 250 and 380 μm, respectively. We also introduced a new, simple, and convenient method for achieving efficient lateral current injection confinement in BH lasers by using the highly resistive LPE-grown Al0.65Ga0.35As (lightly Ge-doped) layer. This technique also automatically self-aligns the current injection stripes to the active stripes.
Conversion gain in mm-wave quasiparticle heterodyne mixers
Authors: Shen T.-M. , Richards P. L. , Harris R. E. , Lloyd F. L.
Published: February 2003

We report the observation of heterodyne mixing in superconductor-insulator-superconductor tunnel junctions with significant conversion gain and with a noise temperature comparable to the photon noise limit. (Double sideband L−1=1.400.14, TM≲1.5 K at 36 GHz.) The mixing arises from the strong nonlinearity in the quasiparticle tunneling currents at voltages comparable to the full energy gap. Gain is observed when the onset of quasiparticle current is sufficiently sharp that quantum effects are important. The observed gain is in good quantitative agreement with calculations based on the work of Tucker. It should make possible the construction of photon-noise-limited microwave heterodyne receivers.
Photoionization cross section and density of interface states in MOS structures
Authors: Greve D. W. , Dahlke W. E.
Published: February 2003

We have measured the electron photoionization cross section and the interface state density in MOS capacitors of two different oxide thicknesses. In both cases good agreement is obtained between optical and nonoptical measurements of the interface state density, and an increase of the state density toward the conduction band is observed. The photoionization cross section increases monotonically with photon energy and also with trap energy increasing from midgap to the conduction band. This behavior is quite different from that observed for bulk states.
Short-circuit memory in electrochromic displays
Authors: Beni G.
Published: February 2003

We prove that direct matrix addressing of electrochromic displays is theoretically possible if an appropriate free-energy barrier for charge transfer across the electrode/electrolyte interface can be introduced. We derive the maximum short-circuit memory of such an electrochromic cell in terms of its intrinsic response time. For response times ∼10 msec and electrolyte breakdown voltages ∼2 V, the maximum memory is ∼20 min at room temperature. The number of lines that could be sequentially matrix addressed in an electrochromic display matrix, under these conditions, spans the range 10–105, which encompasses any practical size of display matrices.
Induced phonon-sideband laser operation of large-quantum-well AlxGa1−xAs-GaAs heterostructures (L
z ∼200–500 Å)
Authors: Coleman J. J. , Dapkus P. D. , Vojak B. A. , Laidig W. D. , Holonyak N. , Hess K.
Published: February 2003

Data are presented on photopumped metallorganic chemically vapor-deposited AlxGa1−xAs-GaAs quantum-well heterostructures with active regions consisting of a large GaAs quantum well (Lz1∼200, 500 Å) coupled to a phonon generating array of seven small GaAs wells (Lz2∼50 Å). Phonon-sideband laser operation below the confined-carrier transitions of the large GaAs quantum well(s) is induced by the large number of phonons generated in the smaller GaAs wells. The induced phonon-sideband laser operation (of a larger quantum well by an array of smaller wells) leads to a measurement of the energy difference between the first-state light- and heavy-hole energies of a 200-Å GaAs quantum well (4.9 meV) and directly to the GaAs L0-phonon energy h/ωL0≈41.0−4.9=36.1 meV.
Fast nondamageable laser-pulse detector using gaseous plasma
Authors: Bergmann Ernest E. , McLellan Edward J. , Webb John A.
Published: February 2003

We investigated pulsed laser radiation detectors in which the emf is generated by the plasma formed when the radiation is focused onto a solid metal surface. We report on measurements made with 10.6-μn laser pulses at peak power levels up to 100 MW. For an evacuated detector, we obtained signals ≳1 kV and subnanosecond rise times into a 50-Ω load. Detector performance is strongly modified with the introduction of a background gas. With one atmosphere of air, the detector produces signals on the order of 1 V and nanosecond response for pulse trains lasting 100 ns, and is thus a good qualitative beam monitor. With argon, krypton, or xenon at pressures on the order of 10 Torr, the detector generates ’’trigger pulses’’ of 250-V amplitude and <0.2-ns rise times. These detectors are indestructable.
Photosensitivity enhancement by H- and He-ion implantation in lead lanthanum zirconate titanate ceramics
Authors: Land C. E. , Peercy P. S.
Published: February 2003

H- and He-ion implantation has been used to increase the photoferroelectric image storage sensitivity of lead lanthanum zirconium titanate ceramics by factors of ∼10 and ∼30, respectively. The increased photosensitivity can be attributed primarily to implantation-produced disorder, which increases the efficiency of carrier photoexcitation and trapping and reduces the exposure energy required to establish nonvolatile space-charge fields. Implantation-induced disorder may also contribute to a substantial increase in photoconductivity in the ion-damaged near-surface region.
Stress wave profiles in cleaved and undamaged 〈111〉 β-BaF2 crystals at 4.0 GPa
Authors: Dandekar Dattatraya P. , Martin Anthony G. , Kelley John V.
Published: February 2003

The results of the present investigation on cleaved and undamaged 〈111〉 crystals of β-BaF2 show no signs of transformation of β- to α-BaF2 under shock compression, consistent with the idea that the transformation does not occur in the undamaged layer of β-BaF2. Further, the results suggest that the deformation of 〈111〉 β-BaF2 crystals is elastic to 4.0 GPa.
Laser annealing of silicon implanted with both argon and arsenic
Authors: Rimini E. , Chu W.-K. , Baglin J. E. E. , Tan T. Y. , Hodgson R. T.
Published: February 2003

Silicon samples implanted with both Ar and As at fluences of 1×1016/cm2 were irradiated with Q-switched Nd:YAG double-frequency laser pulses. Reordering of the damaged layers occurs for 30- and 130-keV Ar implants at about 0.6 and 1.3 J/cm2, respectively. An Ar concentration of the order of (1–3)×1020 atoms/cm3 is retained, while good As substitutionality is observed. The presence of Ar atoms does not seem to inhibit the As-Si reordering during pulsed laser annealing, and likewise the As atoms do not seem to inhibit Ar out-diffusion. This behavior contrasts markedly with the strong coupling found in furnace annealing.
Thermal diffusion of tin in GaAs from a spin-on SnO2/SiO2 source
Authors: Nissim Y. I. , Gibbons J. F. , Evans C. A. , Deline V. R. , Norberg J. C.
Published: February 2003

The thermal diffusion of Sn in GaAs from a spin-on SnO2/SiO2 source is described. The processing steps leading to reproducible electrical charcteristics are presented. Electrical measurements, secondary-ion mass spectroscopy, and Rutherford backscattering analysis have been used to study the diffusion during various processing sequences. The results show that this source can make Sn atoms available for diffusion at very low temperatures and produce heavily doped, shallow n+ layers that may be of interest for GaAs field-effect transistor technology.
Cavity-length stabilization technique for synchronously pumped mode-locked lasers
Authors: Frigo N. , Hemenway C. , Mahr H.
Published: February 2003

We demonstrate a technique for active stabilization of the cavity length of synchronously pumped mode-locked lasers. The technique is general and relies on the ultrashort-pulse forming process itself. It can be implemented in a variety of nonparasitic ways, has high sensitivity to changes in true optical path length of the cavity, and offers the possiblity of long-term stabilization.
Epitaxially grown monocrystalline garnet cathode-ray tube phosphor screens
Authors: Robertson J. M. , van Tol M. W.
Published: February 2003

The technique of liquid phase epitaxy has been used to produce single-crystal garnet phosphor screens for cathode ray tubes. The films were rare-earth-doped yttrium aluminum garnets (YAG’s) grown onto YAG substrates using a PbO:B2O3 flux. We have studied the light output of these layers as a function of film growth temperature, rare-earth activator concentration, and incident power density. With Ce:YAG layers it was possible to use beam power densities up to 108 W/m2 and this produced a radiance of over 105 W/cm2 sr.
Raman shifting of long-pulse-length XeF* laser radiation
Authors: Trainor Daniel W. , Hyman H. A. , Itzkan Irving , Heinrichs R. M.
Published: February 2003

Experiments have been carried out to Raman-shift long-pulse-length XeF* laser radiation in high-pressure molecular hydrogen. Typical output from a one-meter-long, e-beam-pumped XeF* laser was 0.6 J in 0.4 μsec. Significant Raman conversion, primarily into first Stokes radiation, was observed throughout the pump pulse, with an overall energy conversion efficiency of approximately 35%.
Electron-pulsed diffusion of Se in GaAs
Authors: Davies D. Eirug , Ryan Thomas G. , Lorenzo J. P.
Published: February 2003

n + regions with concentrations exceeding 1019 cm−3 have been formed in GaAs by pulse diffusion with an electron beam. The diffusion source is a deposited As2Se3 film which is removed by the pulse without unduly affecting the initial polished appearance of the GaAs. The resulting doped layers are characterized by exceedingly low carrier mobilities. The well-known similar deficiency of pulse-annealed implanted layers would thus appear to be caused by some artifact introduced by the pulse rather than by residual damage unannealed from the implantation. Pulse diffusion should provide an alternative means to implantation for forming n+ contacts in GaAs.
Cr profiles in semi-insulating GaAs after annealing with and without SiO2 encapsulants in a H2-As4 atmosphere
Authors: Eu V. , Feng M. , Henderson W. B. , Kim H. B. , Whelan J. M.
Published: February 2003

The redistribution of Cr in semi-insulating GaAs upon annealing at 860 °C can be greatly reduced by eliminating the use of a SiO2 encapsulant. The annealing schedule utilized a controlled atmosphere technique which insured the thermodynamic stability of the GaAs surfaces and had no tendency to getter Cr. The sample annealed with a SiO2 encapsulant showed a secondary-ion-mass-spectroscopy-measured minimum Cr concentration which was lower by a factor of 20–25 than the original, whereas the comparison of an annealed sample without the SiO2 cap had a minimum Cr concentration which was smaller by a factor of 2. The conversion near the surfaces of semi-insulating Cr-doped GaAs to moderately high-conductivity n type upon annealing can be minimized by using the above technique without an encapsulant.
Hot-carrier relaxation in photoexcited In0.53Ga0.47As
Authors: Shah Jagdeep , Leheny R. F. , Nahory R. E. , Pollack M. A.
Published: February 2003

Photoluminescence spectra of In0.53Ga0.47As reveal the presence of hot carriers with effective temperatures as high as Tc ∼600 K. Variation of carrier temperature with excitation intensity identifies the LO phonon emission process as the dominant carrier cooling mechanism with h/ωLO=34 meV. Comparison with GaAs yields a hot-carrier energy loss rate a factor of 3 smaller for the less polar In0.53Ga0.47As.
Detection of monolayer quantities of oxygen on silicon using energy-dispersive x-ray spectrometry
Authors: Musket R. G. , Strausser Y. E.
Published: February 2003

The sensitivity of energy-dispersive x-ray spectrometry (EDXS) has been determined for the detection of oxygen in thin oxides on silicon. A detection limit of about one monolayer by EDXS was within a factor of 10 of that detected by Auger electron spectroscopy under the analysis conditions employed (i.e., 150 nA of 5-keV electrons for 60 s). Measurements, including in situ sputter-thinning of an oxide of known thickness, were performed in a standard Auger system with an ultrathin-windowed Si(Li) x-ray detector attached. A linear relationship between the oxide thickness and the O(K) x ray intensity was found for thicknesses up to 200 Å. Optimization of the EDXS arrangement by improving the solid angle for x-ray detection and the x-ray takeoff angle should improve the sensitivity for oxygen and other elements with atomic number Z⩾6.
Photoelectrochemistry with p-Si electrodes: Effects of inversion
Authors: Turner J. A. , Manassen J. , Nozik A. J.
Published: February 2003

Reduction of chemical species with redox potentials above the apparent conduction band edge of p-Si were found to be possible with illuminated p-Si in contact with nonaqueous electrolytes. Analysis of the wavelength dependence of the photoreduction current and capacitance data as a function of electrode potential, ac signal frequency, and light intensity shows that this supra-conduction-band-edge reduction is the result of band-edge unpinning, rather than the result of a hot-electron injection process. The band-edge unpinning is caused by the formation of an inversion layer in illuminated p-Si.
Liquid phase epitaxially efficient visible emission from highly doped liquid phase epitaxially grown InP
Authors: Hawrylo Frank Z.
Published: February 2003

Intense visible photoluminescence emission has been observed in liquid phase epitaxially grown InP layers which were heavily doped with group-VI (S, Se, Te) elements. Up to 3% Se and over 1020 cm−3 n-type carrier concentrations have been measured in such layers which exhibit InP crystal structures and lattice parameter.
Calculation of the Auger line at the Si/SiO2 interface
Authors: Kunjunny T. , Ferry D. K.
Published: February 2003

The Auger line shape has been calculated for the surface of (100) silicon, using a semiempirical tight-binding slab model. Chemisorbed oxygen was considered by having the oxygen atom (or molecule) satisfy the double dangling bond of the surface atoms. The presence of the chemisorbed oxygen caused a shift of the outer-layer local density of states in such a manner to create additional structure in the N(E) distribution for the Auger transition. This structure correlates well with such structure reported recently by several experimental groups.
A multitrack ferroelectric array with inherent track access
Authors: Geary J. M.
Published: February 2003

A monolithic array of parallel ferroelectric tracks has been fabricated by selectively etching through a gadolinium molybdate platelet. The tracks project at right angles from a single access track. Domain walls produced at a nucleator move first up the access track and then out across the tracks of the array. Both raster scanning and scanning of a single selected track have been demonstrated. These two modes of operation should find appropriate application to two-dimensional ferroelectric image scanners and to ferroelectric analog read-only memories, respectively.
A lateral microscopic growth model for heterogeneous impurity incorporation during Czochralski crystal growth
Authors: Bauser E. , Rozgonyi G. A.
Published: February 2003

The occurrence of heterogeneous impurity incorporation during growth of Czochralski silicon and germanium crystals is attributed to a microscopic kinetic mechanism of terrace growth. This is deduced from the close correspondence of striation patterns in bulk crystals with terrace traces in GaAs layers grown by liquid phase epitaxy. A simplified but generally applicable model of terrace growth for both epitaxial layers and bulk crystals is presented. The model does not depend on the occurence of constitutional supercooling.
Temperature dependence of metal-nitride-oxide-silicon currents at constant oxide fields
Authors: Fedotowsky A. , Lehovec K. , Park Y.K.
Published: February 2003

The steady-state current through the double dielectric of metal-nitride-oxide-silicon capacitors on p-silicon substrate was measured as a function of temperature for several fixed fields in the silicon oxide of a polarity-promoting hole flow from the silicon. It is shown that the availability of empty recipient trap states for holes tunneling from the silicon into the nitride controls the current. The occupancy of these trap states is governed by Frenkel-Poole detrapping at elevated temperatures and by Fowler-Nordheim tunnel emission from the traps at low temperature. Transient charging measurements support this interpretation.
Polycrystalline-silicon thin-film transistors on glass
Authors: Matsui M. , Shiraki Y. , Katayama Y. , Kobayashi K. L. I. , Shintani A. , Maruyama E.
Published: February 2003

Thin-film transistors are fabricated on polycrystalline silicon on transparent glass using molecular beam deposition at low temperatures. It is found that the transistor characteristics and stability of this device, together with the low-temperature processes utilized, afford potential application to flat display panels.
Electron beam modulation of GaAs metal-semiconductor field-effect transistors
Authors: Wieder H. H. , Davis N. M. , Flesner L. D.
Published: February 2003

Modulation of the surface potential of GaAs Schottky barrier field-effect transistors by 1–6-kV electrons with current densities in the range between 10−5 and 10−3 A/cm2 can produce current gains G⩾105 for electron beam currents pulsed at rates ⩽104 Hz.
Thermal behavior of laser-annealed GaAs studied by helium backscattering spectroscopy
Authors: Amano J. , Pianetta P. A. , Stolte C. A.
Published: February 2003

The thermal behavior of Te-implanted, laser-annealed GaAs was investigated by helium backscattering and channeling analysis in order to determine the role of structural changes on the two-stage reduction in carrier concentration observed with post-laser-anneal heating above 250 °C. Post-laser-anneal heating up to 450 °C caused no observable structural changes in the GaAs or in the substitutionality of the implanted Te. On the other hand, 850 °C post-laser-anneal heating induced the formation of extended defects in the GaAs, and the channeling half-angle of Te was narrowed by about 11%. From those observations, possible models to explain the reduction in carrier concentration are postulated.
Effects of geminate recombination on the photovoltaic characteristics of a-Si:H Schottky barrier solar cells
Authors: Chen I. , Mort J.
Published: February 2003

The photovoltaic characteristics of an a-Si:H Schottky barrier cell have been analyzed theoretically taking into account geminate recombination and the localized state distribution. A comparison of the results with the experimental data in the literature leads to fundamentally different conclusions regarding the limitations of this type of photovoltaic cell. The limitation due to carrier lifetime is unimportant in a cell of typical thickness (∼0.5 μm), while geminate recombination can essentially account for observed recombination losses.
High-conductivity heteroepitaxial ZnSe films
Authors: Besomi Paul , Wessels Bruce W.
Published: February 2003

High-conductivity ZnSe single-crystalline films have been heteroepitaxially deposited on GaAs substrates using open-tube chemical vapor transport. Unintentionally doped films had net donor concentrations of 1014–1016 cm−3 and resistivities of 1–103 Ω cm. Resistivity was found to be dependent upon the zinc partial pressure present during deposition.
The electrical effect of hydrogen on InSb films
Authors: Dawar A. L. , Taneja O. P. , Mathur P. C.
Published: February 2003

Polycrystalline films of n-InSb were exposed to hydrogen at 300 and 500 psi for 2 h. Large changes were observed in the Hall coefficient and mobility, denoting a transfer of donor states to the films. This is believed to involve the in-diffusion of hydrogen, which was found to be irreversible within a period of one month.
Determination of relative impurity concentrations using photoluminescence: A case study of the Si: (B,In) system
Authors: Mitchard G. S. , McGill T. C.
Published: February 2003

We report on a systematic study of the use of photoluminescence for the determination of relative impurity concentrations. The system chosen for the study was Si with a shallow level, B, in the presence of a deeper level, In. The results show that, at sufficiently low concentrations, the photoluminescence intensities can be used to determine the relative impurity concentrations. At higher In concentrations (NIn ≳1015 cm−3) we find that exciton transfer from B to In results in a quenching of the B photoluminescence intensity. For NIn ≳2×1016 cm−3, B photoluminescence was not observed in any sample studied.
Crystallization of amorphous Pr0.27 Co0.73: Magnetic properties and laser-induced coercivity
Authors: Croat J. J. , Chraplyvy A. R. , Herbst J. F.
Published: February 2003

We report magnetic measurements of a Pr0.27 Co0.73 alloy during crystallization from the amorphous state. A maximum room-temperature coercivity of 6.8 kOe developed after an anneal at ∼415 °C. The magnetization of the amorphous material exceeds the crystalline value by a factor of approximately 3. We also demonstrate that small sample regions can be selectively annealed using focused laser radiation, thereby producing magnetically hard regions in a soft magnetic host.
Hypersonic-helium-flow-field measurements with the resonant Doppler velocimeter
Authors: Zimmermann M. , Miles R. B.
Published: February 2003

A low density of sodium atoms seeded into a hypersonic helium flow is used to quantitatively determine flow-field properties. By observing fluorescence from a point as a single-mode dye laser is tuned through the sodium D2 line, the absorption profile may be found. This profile is fitted to a properly weighted sum of Voigt functions to yield the velocity, temperature, and pressure at the observation point. The fluorescence is strong enough to use this technique for qualitative flow-field visualization.
Phonon contribution to double-heterojunction laser operation
Authors: Holonyak N. , Vojak B. A. , Laidig W. D. , Hess K. , Coleman J. J. , Dapkus P. D.
Published: February 2003

Laser data (77 and 300 K) are presented on two photopumped undoped metallorganic chemical vapor deposition AlxGa1−xAs -GaAs heterostructures with active regions consisting of: (i) a thick GaAs layer (Lz1 ∼1500 Å) coupled to an auxiliary quantum-well array of seven small Lz2 ∼50 Å coupled GaAs layers, and (ii) a comparison single thick GaAs layer (Lz2 ∼600 Å) in the form of a conventional double heterostructure (DH). Because of the strengthening of phonon-assisted recombination with temperature, laser operation of the bulk (Lz ≳500 Å) GaAs layers is shifted from h/ω∼Eg at 77 K to Eg −h/ωL0⩽h/ω<Eg at room temperature. This behavior of the bulk DH GaAs layers agrees with that of the reference recombination radiation observed from the auxiliary quantum-well array (wafer ♯1), which recent work indicates is phonon assisted.
Second-harmonic generation in the presence of prism coupling into an optical waveguide
Authors: Sarid Dror
Published: February 2003

We present a coupled wave equation that describes the simultaneous processes of prism coupling into and out of an optical waveguide and second-harmonic generation. The theory applies to both the small- and large-signal regimes, and is presented by universal curves that give the second-harmonic generation efficiency in terms of the scaled parameters of the system.
Efficient simple sealed-off CO laser at room temperature
Authors: Peters P. J. M. , Witteman W. J. , Zuidema R. J.
Published: February 2003

A sealed-off cw CO laser with gold electrodes is described. With this simple device we measured a constant, long-life output power of more than 29 W/m and a maximum efficiency of 15% at room temperature. No auxiliary features, such as a palladium hydrogen extraction tube, are necessary.
Schlieren multimode fiber-optic hydrophone
Authors: Spillman W. B. , McMahon D. H.
Published: February 2003

A multimode fiber-optic hydrophone based upon a Schlieren intensity modulation mechanism is described. The device possesses sufficient sensitivity to detect the Knudson sea noise levels in the frequency range 100 Hz to 1 kHz and to detect static displacements as small as 2.5×10−3 Å. It is not susceptible to phase noise and is relatively insensitive to static pressure head variations. The hydrophone is electrically passive. Ease of fabrication, potential low cost, and compatibility with present multimode fiber-optic technology make this device an attractive candidate for incorporation into practical fiber-optic acoustic sensing arrays.
Electron-beam-induced current investigations of cw laser-annealed silicon
Authors: Mizuta M. , Sheng N. H. , Merz J. L. , Lietoila A. , Gold R. B. , Gibbons J. F.
Published: February 2003

The electron-beam-induced current in As+-implanted Si is investigated after cw laser annealing. These experiments show that the laser power ’’window’’ for successful laser annealing is quite small; low charge collection efficiency usually results. To date, the best annealing results were obtained for a highly overlapping laser scan (100-μm beam with 6-μm scan steps), at a laser power approximately 70 –75% of the power required for melting. At higher laser power, evidence for laser-induced damage has been observed. This evidence suggests that the damage extends several microns below the implanted layer.
Reactive ion beam etching of SiO2 and polycrystalline silicon
Authors: Brown D. M. , Heath Barbara A. , Coutumas T. , Thompson George R.
Published: February 2003

Reactive ion beam etching experiments using a collimated ion beam and the gases CF4, C2F6, and C3F8 have been conducted. At a beam current density of 0.4 mA/cm2 and ion energies from 0.5 to 1 keV the etch rates of SiO2 and polycrystalline silicon were 650 and 65 Å/min, respectively, with C2F6 and C3F8. The etch selectivity was 10 to 1 for these gases though less than 2 to 1 for CF4. No undercutting was observed using this method.
Diffusion and structural relaxation in compositionally modulated amorphous metal films
Authors: Rosenblum M. P. , Spaepen F. , Turnbull D.
Published: February 2003

The interdiffusivity in compositionally modulated (λ≈25 Å) amorphous (Pd85Si15)61/(Fe85B15)89 and (Pd80Au7Si13)70/Fe30 films has been measured by monitoring the satellite of the (000) x-ray scattering peak during isothermal anneals in the range 210–250 °C. Diffusivities as low as 10−22 cm2 s−1 have been measured. It was observed that the diffusivity decreased continuously during the annealing as a result of structural relaxation and settled down to a constant value only after many hours of annealing. The activation energy of the isoconfigurational diffusivity in the Pd-Au-Si/Fe films is 167 kJ mol−1. This value and the time scale of the relaxation are similar to those observed in earlier viscosity measurements, indicating a similarity between the structural defects controlling both transport processes.
Ion beam annealing of semiconductors
Authors: Hodgson R. T. , Baglin J. E. E. , Pal R. , Neri J. M. , Hammer D. A.
Published: February 2003

The first use of an intense pulsed ion beam to anneal ion-implanted semiconductors is reported. Helium ion channeling shows that a single 80-ns pulse 200-keV H+ ions at ∼100 A/cm2 produced good crystallinity in silicon implanted with 1014 As/cm2 at 100 keV.
Effect of geometry and multiple-image interactions on tunneling and I-V characteristics of metal-vacuum-metal point-contact junctions
Authors: Miskovsky N. M. , Cutler P. H. , Feuchtwang T. E. , Shepherd S. J. , Lucas A. A. , Sullivan T. E.
Published: February 2003

A Green’s function formalism has been used to obtain, for the first time, the exact multiple-image interactions for a hyperboloidal-tip–planar-anode model of a metal-whisker point-contact diode. I-V characteristics, including all image interactions, have been calculated for the point-contact junction consisting of electrodes with identical metals. These are compared with results for the parallel-plane diode model with exact and appropriate forms of the image barrier. In contrast to the case of the parallel-plane diode of identical metals, rectification is predicted for the point-contact diode. Significant differences between the calculated I-V curves are found to be a consequence of the different geometries and approximations for the image interactions.
Silicon photodiode for optical channel waveguides
Authors: Goldberg Lew , Reedy Ron , Lee Sing H.
Published: February 2003

An etched mesa silicon photodiode suitable for detecting light propagating in optical channel waveguides has been fabricated. The diode width of 7 μm was slightly less than that of the channel waveguide, thus minimizing junction capacitance and the effect of detection noise caused by unguided substrate light. The fabrication technique can be applied to produce on a single Si wafer multiple photodiodes electrically isolated from each other. Optical energy was coupled from (out-diffused)LiNbO3 channel waveguides into the photodiodes by means of evanescent field coupling.