bluuebunny/crossref_metadata_2025 huggingface dataset:
Monte Carlo calculation of the velocity-field relationship for gallium nitride
Authors: Littlejohn M. A. , Hauser J. R. , Glisson T. H.
Published: February 2003

The Monte Carlo technique has been used to calculate the velocity-field relationship for GaN. The calculation has included polar optical scattering, acoustic scattering, piezoelectric scattering, and ionized impurity scattering. The electron mobility has also been evaluated at low fields as a function of impurity concentration.
Triode optical gate: A new liquid crystal electro-optic device
Authors: Channin D. J.
Published: February 2003

A new liquid crystal field effect electro-optic device is described. Light transmission induced by voltage pulses across two electrodes is modulated or gated by voltage on a third electrode. The three-terminal gating characteristics are applicable to scanning and multiplexing arrays of devices for displays or light valves. A novel enhancement mode is also demonstrated.
Thin films of mischmetal cobalt alloys
Authors: Jain H. , Subbarao E. C.
Published: February 2003

Films of MMCo5 of a few hundred angstroms thickness, where MM is mischmetal (combination of rare earths), were prepared by vacuum deposition. These films were amorphous and could be crystallized as a RCo5 phase by heat treatment.
Properties of infrared cat-whisker antennas near 10.6 μ
Authors: Twu Bor-long , Schwarz S. E.
Published: February 2003

Radiation patterns of 10.6-μ infrared antennas have been obtained experimentally and interpreted by means of a simple theory. It is found that the effective antenna length is equal to the length of the etched portion of the sharpened cat-whisker antenna. This effective antenna length appears to be caused by decoupling of the electromagnetic field across a shape discontinuity of the antenna wire. The results suggest a simple means for defining shape and size of infrared antenna structures.
cw fiber laser of NdLa pentaphosphate
Authors: Weber H. P. , Liao P. F. , Tofield B. C. , Bridenbaugh P. M.
Published: February 2003

cw operation at 1.051 μm of a waveguide laser consisting of a crystalline fiber of Nd0.5La0.5P5O14, 12×12 μm in cross section and 0.68 mm in length, is reported. When longitudinally pumped with a Kr ion laser at 752.5 nm the room-temperature laser threshold was less than 10-mW absorbed power.
Far-infrared reflectivity studies of dielectric function of a Pb-Sn-Te epitaxial film
Authors: Tennant W. E. , Cape J. A.
Published: February 2003

Far-infrared reflectivity measurements form ∼50 to ∼250 cm−1 on a Pb0.82Sn0.18Te epitaxial film (P∼1016 cm−3) on a high-carrier-density substrate (P∼1018 cm−3) of similar composition showed interference oscillations. These detailed reflectivity data were fitted using the standard two-oscillator model with a spatially variable plasma frequency. The fit determines the phonon frequencies, electron and phonon linewidths, high-frequency dielectric constant, and, using existing effective-mass data, the spatial profile of the free-carrier density.
Surface impurities in silver halide films
Authors: Baetzold R. C.
Published: February 2003

Auger spectroscopy has shown that the divalent cation impurities Zn++, Cd++, and Pb++ in the concentration range above 0.1% segregate to the surface of silver halide films. Sputtering of the films shows a layer approximately 10 Å thick at the film-vacuum interface where the impurities accumulate. The surface ratio of impurity to silver ion increases with the total amount of impurity present.
Hole injection into silicon nitride: Interface barrier energies by internal photoemission
Authors: DiMaria D. J. , Arnett P. C.
Published: February 2003

Energy barrier heights at the interfaces of metal–silicon nitride–silicon structures have been measured by internal photoemission as a function of metal electrode material and substrate doping. These measurements have been interpreted in terms of a dominant hole internal photoemission mechanism. Hole energy barriers from the Au, Al, or Mg Fermi level and the Si valence band to the Si3N4 valence band were found to be 1.9±0.1, 3.0±0.1, 4.0±0.1, and 2.1±0.1 eV, respectively.
Ballistic overshoot in the gradient propagation of bubbles in garnet films
Authors: Malozemoff A. P. , DeLuca J. C.
Published: February 2003

We report the first observation of a large ballistic effect in the gradient propagation of magnetic bubble domains in high-mobility garnet films. Using high-speed laser photography to measure bubble position as a direct function of time, we observe a large displacement after the gradient pulse has turned off, with a relaxation time of several microseconds.
Pulsed double−heterostructure GaAs diode lasers in flexural and longitudinal vibrations
Authors: Keller René , Voumard Claude , Weber Horst
Published: February 2003

The deformation behavior of pulsed double−heterostructure diode lasers at both mirror and contact surfaces was investigated by means of an interferometric technique. The diodes, which were only supported by the pressure of a wire connection, showed at the end of a current pulse an elongation and deflection behavior. Longitudinal and flexural vibrations of the diodes were measured after the application of a single current pulse and for the flexural vibrations a resonance behavior was observed during a current pulse train.
Stabilization of the high−temperature phase of MnBi by the addition of rhodium or ruthenium
Authors: Lee Kenneth , Suits J. C. , Street G. B.
Published: February 2003

It has been found that adding Rh or Ru to MnBi is effective in stabilizing the high−temperature β phase (distorted NiAs structure) relative to the low−temperature α phase (undistorted NiAs structure). This effect has been observed in both evaporated thin films and bulk samples. Addition of 1 at.% Rh to bulk MnBi increases the minimum time constant for the β→α transformation by 5 orders of magnitude. Stabilization is important in the use of MnBi for thermomagnetic recording.
Acoustic waveguide with a cladded core geometry
Authors: Boyd G. D. , Coldren L. A. , Thurston R. N.
Published: February 2003

A new type of acoustic waveguide analogous to the clad optical fiber waveguide is described and experimental results are given. Modes exist in this structure which confine the acoustic energy to approximately the core due to the lower acoustical velocity in this region. The waveguide is excited with specially electroded bulk shear transducers bonded to the end surfaces. In the ∼100−MHz region both radial and torsional type modes may be attractive for long−delay (near 1 msec) low−loss serial memory applications.
Technique for capacitively voltage weighting interdigital surface acoustic wave transducers
Authors: Tanski William J.
Published: February 2003

A simple method is presented by which the voltage between electrodes on an interdigital surface acoustic wave (SAW) transducer is varied by means of capacitive voltage division. Using this technique, a capacitor is added in series with the capacitance of an electrode pair through the use of a single photolithographic mask. The capacitance values are determined by geometry alone. This method permits voltage weighting both transducers of a device, and it minimizes the effects of diffraction. Experimental results are presented in which the sidelobes in a SAW filter have been reduced to 45 dB below the passband level.
Connections and disconnections on integrated circuits using nanosecond laser pulses
Authors: Cook P. W. , Schuster S. E. , von Gutfeld R. J.
Published: February 2003

Nanosecond pulses from a focused nitrogen pumped dye laser have been used to connect and disconnect conductors on FET chips. Experiments on connections between n+ diffusion layers and aluminum, separated by an insulating layer of SiO2, show promise for high yield and reliability. The connections have Ohmic characteristics. Sectioned laser connections were examined with an electron microprobe and microscope in order to examine physical details of the connection process.
Picosecond optoelectronic switching and gating in silicon
Authors: Auston D. H.
Published: February 2003

Quasimetallic photoconductivity produced by the absorption of picosecond optical pulses in silicon transmission line structures has been used to devise electronic switches and gates which can be turned on and off in a few picoseconds. Electrical signals as large as 100 V can be switched by a few microjoules of optical energy. The switching speed was measured by correlating the response of two transmission gates in tandem, each having an aperture time of 15 psec.
Isotope separation by optically pumped ionizing collisions
Authors: Harris S. E. , Lidow D. B.
Published: February 2003

We propose a modification of the selective two−step photoionization technique which greatly improves its efficiency. A third species with a strong resonance transition is added to the mix of isotopes which it is desired to separate. Incident optical energy is radiatively and collisionally trapped in this catalytic species. Selective ionization of excited step one species is accomplished by long−range ionizing collisions.
Observation of coherent anti−Stokes Raman scattering from liquid water
Authors: Itzkan Irving , Leonard Donald A.
Published: February 2003

The line shape of the coherent anti−Stokes (CAS) Raman band at 3200 cm−1 in liquid water has been measured using two independent but synchronized pulsed nitrogen laser pumped dye lasers as excitation sources. The observed CAS spectral shape differs significantly from the corresponding classical Stokes Raman profile and can be explained by coherent interference between the resonant and nonresonant scattering. Such effects are important in CAS applications involving aqueous media and in other situations such as high−temperature gases, i.e., T≳1000 °K, where the Raman resonance is significantly broadened.
A new grading layer for liquid epitaxial growth of GaxIn1−xAs on GaAs substrate
Authors: Nagai Haruo , Noguchi Yoshio
Published: February 2003

A small amount of P has been added to a Ga−In−As melt for liquid phase epitaxial growth of GaxIn1−xAs on GaAs substrate. By this technique, GaxIn1−xAs layers of low etch−pit density and wide composition range have been grown on GaxIn1−xAsyP1−y continuously graded composition layers.
Pulsed ion lasers excited by the pinch effect
Authors: Katzenstein J. , Lovberg R. H.
Published: February 2003

Previous experimental work has demonstrated strong laser action on the ionized lines of argon and xenon in pinch discharges in these gases. This laser action is correlated in time with the minimum contraction of the discharge. The laser output power, however, was found to saturate with bank voltage, and to be maximized at a critical initial filling pressure. These phenomena, obtained empirically in the initial work, can be shown to be the consequences of a generalized impedance matching problem, and hence correspond to the optimization of the transfer of stored bank energy to the pinched plasma. Thus, rational scaling laws can be derived for this type of laser.
Heterojunction formation using amorphous materials
Authors: Dunn B. , Mackenzie J. D. , Clifton J. K. , Masi J. V.
Published: February 2003

Heterojunctions have been fabricated by depositing glass films onto single−crystal silicon substrates. Junction behavior has been exhibited regardless of the electrical or chemical properties of the glass film. The observed characteristics are a function of these properties. Current rectification, variable capacitance, sharp reverse breakdown, and photovoltaic responses have been observed.
Picosecond response of a high−repetition−rate CS2 optical Kerr gate
Authors: Ippen E. P. , Shank C. V.
Published: February 2003

An optical Kerr gate is operated at high repetition rates using picosecond pulses from a mode−locked cw laser. A new mode of gate operation is demonstrated in which incremental transmission is linearly proportional to pump power. Direct temporal measurement of a 2.1−psec response time of the optical Kerr effect in CS2 is reported.
Analysis of surface layers by the channeling technique: Beam energy dependence
Authors: Della Mea G. , Drigo A. V. , Lo Russo S. , Mazzoldi P. , Yamaguchi S. , Bentini G. G.
Published: February 2003

The surface peak of the channeling energy spectrum has been investigated as a function of energy of the incident beam. An increase of the surface peak value with energy has been observed for axial channeling in silicon 〈110〉, germanium 〈111〉, molybdenum 〈111〉, and vanadium 〈100〉 and 〈110〉 crystals with low surface contamination. The influence of oxide layers on the energy dependence effect has been investigated on silicon crystals.
Electron−hole pair creation energy in SiO2
Authors: Ausman G. A. , McLean F. B.
Published: February 2003

The average energy W required to create an electron−hole pair in SiO2 has been determined to be approximately 18 eV by considering the energy loss of fast electrons in solids. This energy loss occurs primarily by plasmon production and subsequent decay of the plasmons into electron−hole pairs. It is also demonstrated that recent data on electron−irradiated SiO2 films can be explained remarkably well by a columnar recombination model. The extrapolation to infinite electric field of the columnar model fit to the data yields a value for W which is in excellent agreement with the value obtained from the energy loss calculation.
Oxygen sensors using CoO ceramics
Authors: Logothetis E. M. , Park K. , Meitzler A. H. , Laud K. R.
Published: February 2003

Ceramic CoO has been found to be a material suitable for oxygen sensing. The CoO sensor has good sensitivity and fast response time and appears particularly suited for applications involving high temperatures and corrosive or contaminating environments, e.g., combustion processes.
Ion effects in relativistic diodes
Authors: Poukey J. W.
Published: February 2003

In relativistic diodes, ions are emitted from the anode plasma surface. The space charge of these ions enhances the electron emission. One−dimensional analysis and two−dimensional computer simulation are used to show the necessity of including this effect in any realistic diode theory.
Influence of implanted dose on the recrystallization of Si amorphous layer
Authors: Baeri P. , Campisano S. U. , Ciavola G. , Foti G. , Rimini E.
Published: February 2003

The channeling effect technique has been used to investigate the annealing of the ’’amorphous’’ layer produced in Si by 40−keV Pb implants with fluences ranging between 5×1013 and 5×1015 ions/cm2. The amount of residual disorder, after an anneal of 30 min at 650 °C, shows a dose dependence and increases strongly with Pb fluence, thus indicating the influence of the dissolved lead atoms in the recrystallization process.
Improved optical quality of AgGaS2
Authors: Matthes H. , Viehmann R. , Marschall N.
Published: February 2003

Single crystals of AgGaS2 for nonlinear optical applications were grown by the Bridgman−Stockbarger technique. It was possible to prepare 0.5−cm cubes free of lamellar twins from the central region of the boules. Room−temperature absorption of as−grown crystals was below 0.3 cm−1 through the whole transmission range. After an annealing process with additional sulfur, absorption was reduced to α<0.1 cm−1 in the wavelength range λ=0.9−8.5 μm.
Single−crystal β−SiC films by reactive sputtering
Authors: Haq K. E.
Published: February 2003

Single−crystal β−SiO films were deposited by reactive sputtering on α−SiC substrates at temperatures as low as 1150 °C at a growth rate of 3 Å/sec. Elemental Si was used for target material. The carbon was provided by introducing a hydrocarbon gas in the reaction chamber. Initial results indicate that the process is highly promising.
Formation of field−reversing ion rings using microsecond ion pulses
Authors: Kapetanakos C. A. , Parker R. K. , Chu K. R.
Published: February 2003

Field−reversing ion rings may be formed using microsecond ion pulses. The short−circuit of the anode−cathode gap caused by the cathode plasma is delayed by placing the diode inside a nonsymmetric cusped magnetic field.
Determination of semiconductor−metal contact resistance by an angle−dependent geometrical magnetoresistance method
Authors: Gútai L. , Mojzes I.
Published: February 2003

A simple method has been developed to separate the bulk and contact resistances of semiconductor devices measuring the angle dependence of the geometrical magnetoresistance. The performances and the efficiency of the method have been proved by measurements made on Gunn diodes. The accuracy is better than 0.5% of the total device resistance.
Simple TEA laser geometry with volumetric photoionization
Authors: Reits B. J. , Olbertz A. H. M.
Published: February 2003

A weak uv source conditions a CO2 laser gas discharge with the aid of the seed gas tri−n−propylamine. Rich mixtures and high input energy densities can be used, resulting in extremely high peak powers.
Mössbauer study of η phase in Fe−Ge binary system
Authors: Eliezer D. , Nadiv S. , Ron M.
Published: February 2003

The Mössbauer spectrum data of η−FexGe was determined at room temperature and liquid−nitrogen temperatrue. It was found to be the same for the composition x=1.23 and x=1.11. X−ray diffraction results are in good agreement with published data.
Planar domains and domain wall structures of bubbles in Permalloy−coated garnet films
Authors: Suzuki R. , Takahashi M. , Kobayashi T. , Sugita Y.
Published: February 2003

The Bitter technique has revealed two kinds of planar domains in the Permalloy overlays associated with bubbles in Permalloy−coated garnet films. Measurements of dynamic properties of bubbles have shown that all the bubbles in these films have either zero or two Bloch lines. In addition, it has been clarified that the number of Bloch lines in the domain walls depends on the kind of planar domains through exchange interaction across the interface between garnet and Permalloy.
Gamma−ray spectroscopy with single−carrier collection in high−resistivity semiconductors
Authors: Malm H. L. , Canali C. , Mayer J. W. , Nicolet M−A. , Zanio K. R. , Akutagawa W.
Published: February 2003

With the standard plane−parallel configuration of semiconductor detectors, good γ−ray spectra can only be obtained when both electrons and holes are completely collected. We show by calculations (and experiments) that with contacts of hemispherical configuration one can obtain γ−ray spectra of adequate resolution and with signal heights of nearly full amplitude even when only one type of carrier is collected. Experiments with CdTe detectors for which the μτ product for electrons is about 103 times that of the holes confirm these calculations. The adoption of hemispherical contacts thus widens the range of high−resistivity semiconductors potentially acceptable for γ−ray detection at room temperature.
Crystal orientation dependence of residual disorder in As−implanted Si
Authors: Müller H. , Chu W. K. , Gyulai J. , Mayer J. W. , Sigmon T. W. , Cass T. R.
Published: February 2003

MeV 4He+ channeling effect measurements combined with transmission electron microscopy (TEM) and Hall effect measurements were employed to study the orientation dependence of the amount of damage remaining after anneal of 200−keV As−implanted Si. The residual disorder after high−temperature annealing was found to depend upon the crystal orientation. For 〈111〉−oriented Si, anomalously high residual disorder was found in the dose region of 1015/cm2 by both the TEM and channeling measurements. Significantly less disorder was found in 〈100〉− and 〈110〉−oriented Si, the latter exhibiting essentially no residual disorder. The electrical activity of the implanted layer was consistent with the orientation dependence observed.
Air−combustion product N2−CO2 electric laser
Authors: Douglas−Hamilton D. H. , Sutton G. W. , Westra L. , Lowder R. S.
Published: February 2003

Efficient electron−beam sustainer CO2 laser action has been obtained in H2 : N2 : CO2 mixtures, using H2 as CO2ν2 deactivant. This opens up the possibility of using a fuel−rich hydrocarbon combustion product as a readily obtained laser gas mixtures, since such a mixture can be generated containing free H2. Efficient electron−beam sustainer CO2 laser action is predicted in the combustion exhaust products of the hydrocarbon fuels such as JP−4. A specific output J∼50 J/l atm is anticipated for an initial temperature Tgo=300 °K. Experimental measurement of laser output from JP−4 exhaust has been made in an electron−beam sustainer EDL. A 23−μsec duration discharge with ne∼3×1012 cm−3, E/N∼2.3×10−16 V cm2 was produced. Output J∼50 J/l atm was obtained for Tgo=211 °K. A 5−μsec delay in predicted laser onset and laser output 40% lower than theoretical were observed.
Homojunction fabrication in CuInSe2 by copper diffusion
Authors: Tomlinson R. D. , Elliott E. , Parkes J. , Hampshire M. J.
Published: February 2003

Rectifying p−n junctions have been fabricated in single crystals of CuInSe2 by diffusion of copper at relatively low temperatures. Some evidence of device instability at room temperature has been obtained.
Subnanosecond tunable dye laser pulse generation by controlled resonator transients
Authors: Lin Chinlon , Shank C. V.
Published: February 2003

A general technique for subnanosecond pulse generation from laser−pumped dye lasers is described. The technique makes use of the resonator transients. These transients are in the form of damped relaxation oscillation and their durations can be controlled by proper choices of photon cavity decay time and pumping level. High−repetition−rate tunable dye laser pulses of subnanosecond durations have been obtained from N2 laser pumped dye solutions in the near−uv and visible regions. These tunable subnanosecond pulses should provide useful excitation sources for nanosecond absorption and fluorescence spectroscopy.
Static technique for precise measurements of surface potential and interface state density in MOS structures
Authors: Ziegler K. , Klausmann E.
Published: February 2003

A new static technique for a very accurate measurement of charge, surface potential, low−frequency capacitance, interface charge, and interface state density in MOS structures is presented. A comparison with the conductance method is made. For a 〈111〉−oriented n−type silicon wafer, oxidized in dry oxygen and annealed in hydrogen, the distribution of the interface state density is shown over an energy range of 0.9 eV within the energy gap.
Continuously tunable submillimeter wave source
Authors: Piestrup M. A. , Fleming R. N. , Pantell R. H.
Published: February 2003

A method for spanning the 100−1000−μ portion of the spectrum with continuously tunable coherent radiation is described. The approach is based upon laser light scattering from the long−wavelength side of the A1−symmetry soft mode in LiNbO3. In contrast with other techniques, this method uses a single fixed−frequency pump source, requires no magnetic field, provides continuous rather than discrete tuning, can cover most of the 100−1000−μ range, operates at room temperature, and is simple to tune. The experimental data show that tuning was obtained from approximately 150 to 700 μ.
Backside−illuminated Pb1−xSnxTe heterojunction photodiode
Authors: Andrews A. M. , Longo J. T. , Clarke J. E. , Gertner E. R.
Published: February 2003

The need for a long−wavelength infrared detector that makes more efficient use of the available radiation has led us to construct a backside−illuminated Pb1−xSnxTe heterojunction in which the radiation passes through a transparent substrate and is absorbed in the active region behind a p−n junction. This device permits a selectivity in the spectral bandwidth of the device due to the short−wavelength cut−on properties of the transparent PbTe substrate or an epitaxial Pb1−xSnxTe filter layer. Additionally, an effective increase in optical area is achieved because the radiation incident upon the sloping sides of the mesa is internally reflected into the junction region due to the index of refraction mismatch between air and PbTe; thus with this design the optical area which gives rise to the signal current is larger than the electrical area which is the source of noise. Laboratory measurements on devices of this construction verify these properties and show that a peak Dλ greater than 1011 cm Hz1/2 W−1 has been obtained at an operating temperature of 77 K.
Completeley optical coincidence logic employing a dye laser
Authors: Johnson E. J. , Riseberg L. A. , Lempicki A. , Samelson H.
Published: February 2003

We report the theory and experimental demonstration of a laser device which performs the functions of binary arithmetic completely optically. The coincidence circuit employs polarization coding of the logic variables and is based upon the bistable polarization behavior of a dye laser in a birefringent cavity.
Theory of short−wavelength lasers from recombining plasmas
Authors: Jones Walter W. , Ali A. W.
Published: February 2003

Starting with a plasma of fully stripped ions (arbitrary Z) with an initial temperature and electron density, the set of rate equations governing the population densities of all discrete levels of hydrogenlike ions are solved. The results (population inversion and gain) are presented for a variety of cases, hydrogen through carbon, with emphasis on short−wavelength lasers.
Laser oscillation from quantum states in very thin GaAs−Al0.2Ga0.8As multilayer structures
Authors: van der Ziel J. P. , Dingle R. , Miller R. C. , Wiegmann W. , Nordland W. A.
Published: February 2003

We report optically pumped laser oscillation from multilayer heterostructures consisting of alternating layers of GaAs and Al0.2Ga0.8As. Very thin GaAs layers (50−500 Å) exhibit one−dimensional bound states above the band gap of bulk GaAs. The laser oscillation occurs at energies which are slightly below the exciton associated with the lowest energy n=1 bound state.
Push−pull thin−film optical modulator
Authors: Webster J. C. , Zernike F.
Published: February 2003

An electro−optic amplitude modulator was made by placing two channel−defined waveguide phase modulators in the legs of a Jamin interferometer. Using a novel detection method, modulation was observed up to 1.8 GHz, although the roll−off in the modulator response started at about 750 MHz. Full amplitude modulation was produced by 17 V, giving a power band width characteristic for the separate phase modulators of 200 μW/MHz for a modulation index of 1 rad.
GaAs concentrator solar cell
Authors: James L. W. , Moon R. L.
Published: February 2003

For terrestrial applications, the figure of merit for photovoltaic solar energy conversion devices is watts output per dollar of cost. AlGaAs/GaAs heterojunction cells have a very favorable watts per dollar figure of merit when used at high values of sunlight concentration. An experimental 1/2−in.−diam cell was operated in air mass 1.4 sunlight with an output power density of 4.52 W/cm2 at an effective concentration of 312 suns with a power conversion efficiency of 17.5%. The same cell was operated at 200 °C with an output power density of 3.45 W/cm2 at a 14% efficiency. The efficiency of the cell was 23% with a fill factor of 0.85 at a lower concentration ratio which is obtainable using simple concentrator schemes.
Spatially coherent radiation from an array of GaAs lasers
Authors: Philipp−Rutz Elisabeth M.
Published: February 2003

Spatially coherent radiation from a monolithic array of three homostructure GaAs lasers is reported. The three lasers, with their mirror faces antireflection coated, are operated in external optical cavity built of spherical lenses and plane mirrors. The spatially coherent beam formation makes use of the Fourier transformation property of the internal lenses. The transverse mode control is performed by a spatial filter. The optical peak power at room temperature of the device was measured to be 5 W, three times the power of a single laser in the array. From the synthesized far−field distribution which was evaluated, we conclude that the laser radiation is of spatial coherence.
Energy analysis of large−angle keV electron scattering from solid targets
Authors: Schmoranzer H. , Grabe H. , Schiewe B.
Published: February 2003

In a new technique for studying the scattering of fast electrons (E0⩾10 keV) into large angles (ϑ≳π/2) from solid targets the intensity and the energy distribution of scattered electrons are analyzed by means of silicon surface barrier detectors in the single−electron counting mode. Results of such studies at a scattering angel of 108° are reported for self−supporting gold foils of various thicknesses between 230 and 1505 Å. The high−intensity measuring accuracy recommends this method for precision determination of foil thicknesses.
Scanning electron microscope investigation of electric activity of stacking faults in silicon epitaxial layer
Authors: Kato T. , Matsukawa T. , Shimizu R.
Published: February 2003

Comparing the images of stacking faults obtained by a scanning electron microscope (SEM) with those obtained by the optical method, we found that not all of the existing faults are observed in an EBIC image of SEM and that the stacking faults which give no contrast in the EBIC image show no preferential etching in Sirtl etchant.
Mutual doping effects between epitaxial ZnS films and GaAs substrates
Authors: Espinosa G. P. , Lim T. C. , Cory E. S. , Zucca R. , Hengstenberg D. H.
Published: February 2003

The problem of strong self-activated luminescence in undoped ZnS films grown on GaAs substrates by chemical vapor deposition is analyzed. Tests made by changing substrates in conjunction with photoluminescence and optical transmission measurements are described. It is concluded that mutual doping effects take place between the ZnS film and the GaAs substrate with Ga doping the ZnS films while Zn dopes the GaAs substrate.
Fowler-Nordheim tunneling and temperature effects in electrical conductivity of metal oxide varistors
Authors: Fix Margaret , Soln Josip
Published: February 2003

The validity of Fowler-Nordheim tunneling as an electrical conduction mechanism in MOV materials was investigated in a wide temperature range. Despite the fact that, in high-field regions, the current-voltage curves conform to the relation I=B exp(−γ/V), which is formally consistent with Fowler-Nordheim tunneling, we find that the parameters B and γ are strongly temperature dependent above 60 °C. The question then arises as to whether the fit of the above relation to the I-V curves is more accidental than an indication of the Fowler-Nordheim tunneling mechanism in the whole temperature range.
Room-temperature heterojunction laser diodes of InxGa1−xAs/InyGa1−yP with emission wavelength between 0.9 and 1.15 μm
Authors: Nuese C. J. , Olsen G. H.
Published: February 2003

Vapor-grown p-n heterojunction laser structures of InxGa1−xAs/InyGa1−yP have been prepared with laser threshold current densities as low as 15 000 A/cm2 at room temperature and 1000 A/cm2 at 77 °K. Emission wavelengths between 1.025 and 1.15 μm have been obtained at 300 °K.
Thermal blooming compensation using coherent optical adaptive techniques (COAT)
Authors: Bridges William B. , Pearson James E.
Published: February 2003

Real-time compensation for thermally induced beam distortion has been demonstrated using a phase-adaptive aperture subdivided into 18 elements coupled with an 18-channel multidither servo system. The results were obtained using an argon ion laser and a nonlinear liquid cell placed in the near field of the transmitted beam. The system increased the peak beam irradiance by more than a factor of 4 at the highest power used and reduced the beamwidth by a factor of 5.4 from the uncorrected bloomed case. A comparison with predictions from existing theory is given.
Fast frequency stabilization of a cw dye laser
Authors: Barger R. L. , West J. B. , English T. C.
Published: February 2003

A system is described for stabilizing a cw dye laser frequency to a high-finesse optical cavity. The length of this optical cavity is locked to a CH4-stabilized He-Ne laser with a tunable frequency-offset technique. A very fast servo system using an intracavity KD*P crystal), a long dye laser cavity, and the stabilized optical cavity result in an absolute frequency stability of 1 kHz for an integration time of 10−4 sec and 300 Hz for 300 sec. Intensity is stabilized to one part in 104.
Hole injection into silicon nitride: Dark current dependence on electrode materials and insulator thickness
Authors: Arnett P. C. , DiMaria D. J.
Published: February 2003

Dark currents in MNS capacitors are studied as a function of metal electrode material and insulator thickness. Dark currents sensitively reflect different electrode materials for thin (∼200 Å) nitride films. Thus, it is found that high-work-function metals increase conduction under metal positive bias by enhanced hole injection and low-work-function metals increase conduction under metal negative bias by enhanced electron injection. Similar polarity differences are observed betwen n-type and p-type degenerate Si substrates. These contact differences disappear as the nitride becomes thicker and the thickness of trapped space-charge layers near the contacts becomes small compared to the nitride thickness.
High-forward-voltage phenomenon in injection GaAs/Ge heterojunctions
Authors: Jain F. C. , Melehy M. A.
Published: February 2003

A significantly high non-Ohmic forward voltage has been observed in n-GaAs/p-Ge and p-GaAs/n-Ge injection heterojunction diodes which have hard reverse electrical characteristics and whose wide-gap emitters were of relatively low doping levels. Theory and experiment are compared and conditions for enhancing this phenomenon are stated. An SEM micrograph of the grown Ge epitaxial layer is included and growth conditions are described.
GaAs-AlxGa1-xAs injection lasers with distributed Bragg reflectors
Authors: Reinhart F. K. , Logan R. A. , Shank C. V.
Published: February 2003

Room-temperature operation of an optically integrated double heterostructure (DH) GaAs-AlxGa1-xAs injection laser with a distributed Bragg reflector (DBR), with threshold current densities of 5 kA/cm2 is reported. The DBR was in the form of a third-order grating which was ion milled on a passive single heterostructure (SH) waveguide section with the latter taper coupled to the active DH section. The observed half-power spectral bandwidth was ≲1 Å. A highly collimated beam output with a half-power divergence angle of ≲0.3° was also achieved by coupling the scattered light from the oil-immersed grating at the Bragg angle with a prism.
Zinc-oxide–on–silicon acoustically scanned imager with positive sensitivity and storage capabilities
Authors: Coldren L. A.
Published: February 2003

The use of remotely launched acoustic surface waves to scan image information on a zinc-oxide–on–silicon monolithic geometry is demonstrated. The dynamic range for the readout can be greatly enhanced by using pulsed bias signals which invert the surface of the n-on-n+ silicon substrate. Images may also be stored in the form of trapped charge replicas in the zinc oxide, and subsequently they may be nondestructively read out using the scanning surface waves.
cw chemical transfer CO2 laser
Authors: Benard D. J.
Published: February 2003

The combustion of Mg vapor in N2O with He and Co2 diluents in a low-loss coaxial laser cavity has resulted in cw oscillation at 10.6 μm. The performance characteristics of the flame laser in a coaxial geometry were found to differ significantly from those expected on the basis of previous gain measurements taken in a transverse flow configuration.
Laser action on the 342-nm molecular iodine band
Authors: Ewing J. J. , Brau C. A.
Published: February 2003

A new laser operating on the 342-nm band of I2 is reported. Electron-beam-excited mixtures of argon with CF3I and HI produced this I2 laser. The excited state of this laser is probably formed by ion recombination reactions, and a plausible mechanism is given.
Low-threshold room-temperature double-heterostructure GaAs1−xSbx/AlyGa1−yAs1−xSbx injection lasers at 1-μm wavelengths
Authors: Nahory R. E. , Pollack M. A.
Published: February 2003

Double-heterostructure (DH) injection lasers based on the GaAs1−xSbx/AlyGa1−yAs1−xSbx system have been fabricated using liquid phase epitaxial growth techniques and operated at room temperature at wavelengths in the 1-μm region. The observed room-temperature threshold current densities, as low as 2100 A cm−2, are comparable to those of GaAs/AlGaAs devices of similar geometry.
Electronic structure of Al and Si dissolved in transition or noble metals studied by soft x-ray spectroscopy
Authors: Tanaka K. , Matsumoto M. , Maruno S. , Hiraki A.
Published: February 2003

K β emission spectra from Al and Si dissolved in transition (Fe and Ni) or noble (Cu) metals as dilute impurities (∼10 at.%) were investigated. In the alloys of the same host metals the spectra of Al and Si bear a striking resemblance to each other. However, there are several important differences between the shapes of the spectra from transition- and noble-metal-based alloys. All these features of the spectra can be reasonably interpreted in terms of the theoretical calculation by Terakura on the energy distribution of the local density of states of the impurity atoms.
Excited state absorption and laser emission from infrared laser dyes optically pumped at 532 nm
Authors: Decker C. David
Published: February 2003

Efficient near-infrared dye laser emission has been achieved in the 838–923-nm range by use of a frequency-doubled Nd:YAG laser as the optical pump for various polymethine dyes. Experimental evidence of 1064-nm quenching of the dye laser emission is reported. Strong excited state absorption (ESA) effects are observed for the dye IR-140 at the 532-nm pump wavelength. This excited state absorption results in an experimentally determined optimum pump power density of 50–60 MW/cm2 for maximum dye laser efficiency. Such excited state absorption may thus be a limiting factor in the power scaling of pulsed dye lasers.
Enhanced breakdown voltage in planar metal-overlap laterally diffused (MOLD) Schottky diodes
Authors: Rusu A. , Bulucea C.
Published: February 2003

A novel uniform-avalanche structure is presented consisting of a planar metal-overlap laterally diffused (MOLD) Schottky diode. This structure has been proved to be free of edge breakdown by numerical two-dimensional field calculations. Experimentally obtained aluminum-silicon MOLD Schottky diodes have shown enhanced breakdown voltage in comparison with simultaneously processed standard planar Schottky diodes.
New type of homointegrated and heterointegrated circuits
Authors: Jain F. C.
Published: February 2003

The use of GeO2 as a stable mask for the selective growth of epitaxial Ge layers through unmasked windows on Ge substrates or on previously deposited Ge layers in GaAs substrates is here described. In both cases, the Ge epitaxial layers have been grown at a relatively low temperature, 330–420 °C, using the GeI2 disproportionation reaction. The surfaces of the oxide and the Ge layers grown in regions surrounded by GeO2 appear to be mirror smooth when observed with a scanning electron microscope up to 11 500× magnification. The oxide-germanium boundary has been found to be free from preferential growth of Ge. New applications of this technique to Ge homointegrated circuits (e.g., Ge layers grown on Ge-or Cr-doped semiinsulating GaAs substrates) and Ge/GaAs heterointegrated circuits are discussed. Also described is the possibility to integrate other materials and new heterojunction devices compatible with Ge and several other devices which are not feasible in Si alone.
Electronic nature of amorphous threshold switching
Authors: Petersen Kurt E. , Adler David
Published: February 2003

Four distinct sets of experiments have been carried out to determine the size of the conducting filament in the on state of an amorphous threshold switch as a function of steady-state current. It is found that the filament is much wider (e.g., 20 μm in diameter at 50-mA current) than is compatible with the current densities necessary for thermally induced switching. An upper limit of 60 °C can be established for the maximum temperature rise in the material for on-state currents between 10 and 200 mA. This establishes the electronic nature of the on state.
Electronic tunneling currents at optical frequencies
Authors: Faris S. M. , Fan B. , Gustafson T. K.
Published: February 2003

Rectification characteristics of nonsuperconducting metal-barrier-metal junctions as deduced from electronic tunneling theory have been observed experimentally for optical frequency irradiation of the junction.
Sparklike domain pattern and hysteresis loops of amorphous Gd-Fe alloy films
Authors: Imamura Nobutake , Mimura Yoshinori , Kobayashi Toshihiko
Published: February 2003

We studied the domain structure and the hysteresis loop of amorphous GdxFe1−x alloy films having perpendicular easy axis anisotropy, and found that the domain pattern, just after reversal at the nucleation field, was sparklike where the strip domain diverged radially from one point to all the area of the sample. The nucleation field Hn was strongly dependent on the maximum magnetizing field Hm for Hm<2 kOe. In the region Hm≳2 kOe, however, the value of Hn was almost constant at 450 Oe.
Effects of gravitationally induced melt removal on cw laser melt-through of opaque solids
Authors: Robin James E. , Nordin Paul
Published: February 2003

A simple model is presented that describes the enhancement of cw laser melt-through of opaque solids due to gravitationally induced melt removal. It is shown that a stationary target whose front surface is oriented at an angle from the horizontal may experience significant reduction in melt-through time due to laminar flow of molten material. As a direct consequence of the high viscosity of the melt, the rate of melt removal is related to the cube of the melt thickness. This model shows that gravitational enhancement effects can be quite significant for thick targets.
Stimulated Raman scattering at kHz pulse repetition rates
Authors: Ammann E. O. , Falk Joel
Published: February 2003

Stimulated Raman scattering (SRS) has been achieved at kHz pulse repetition rates. The Raman oscillator consists of a lithium iodate crystal placed inside a Nd:YAlO3 laser, with feedback provided at the Stokes wavelengths by mirrors surrounding the crystal. First and second Stokes outputs at 1.18 and 1.31 μm, respectively, were generated from oblique longitudinal-optic (LO) phonons in the lithium iodate. These results open the possibility of realizing substantial average output powers from Raman oscillators for the first time.
Rotational population transfer in HF
Authors: Hinchen J. J.
Published: February 2003

Population transfer between rotational levels in HF was observed using double resonance with two HF lasers. Rates for the transfer in v=1 from J=3 to J=4, 5, 6, and 7 were found in the range of 107 sec−1 Torr−1. The rates depended on both gas pressure and on the ΔJ separation between levels of transfer.
Complementary domain pyroelectric detectors with reduced sensitivity to mechanical vibrations and temperature changes
Authors: Byer N. E. , Stokowski S. E. , Venables J. D.
Published: February 2003

LiTaO3 pyroelectric detectors have been fabricated in a novel complementary domain configuration that reduces the interference from vibrational noise sources and from changes in ambient temperature by over an order of magnitude relative to the performance of conventional pyroelectric detectors. Detectors made in this complementary domain configuration exhibit D’s in excess of 109 cm Hz1/2 W−1, and the measured D’s degrade less than 10% in the presence of accelerations as great as 0.05g in a 1-Hz bandwidth, or temperature changes of 10 °C/min.
Comment on ’’Evidence for electronic stopping in ion implantation: Shallower profile of lighter isotope 10B in Si’’
Authors: Vaidyanathan K. V. , Chatterjee Pallab K. , Streetman B. G.
Published: February 2003

A recent paper bases several conclusions regarding electronic and nuclear stopping powers of silicon for implanted boron on a few capacitance-voltage measurements of impurity profiles. We suggest here that the accuracy of C-V data is insufficient to distinguish small changes in projected range, and that measurements with better resolution are required.
Frequency stabilization and absolute frequency measurements of a cw HF/DF laser
Authors: Eng R. S. , Spears D. L.
Published: February 2003

A transverse-flow mixing HF/DF laser transition was frequency stabilized to better than 500 kHz relative to the second harmonic of a CO laser using a heterodyne technique. An absolute frequency of 110 725 697.4±7 MHz was measured for the 1-OP (6) line of the HF laser, which represents a factor of 100 improvement in accuracy over existing data.
Magnetic circular dichroism determination of the effects of O2 and N2 annealing on single-crystal YIG(Si)
Authors: Antonini B. , Geller S. , Paroli P. , Tucciarone A. , Colville A. A.
Published: February 2003

Single-crystal YIG(Si), containing 0.12 Si4+ per formula unit, has been subjected to oxygen and nitrogen annealing and the effects investigated by measurements of magnetic circular dichroism and of the photomagnetic properties. The results support the view that both the dichroic and the photomagnetic centers are Fe2+ ions and that both cation and oxygen vacancies are present in the crystals. The Fe2+ content is increased and decreased in a reversible fashion, along with simultaneous opposite variations of the oxygen vacancies, up to a total variation of approximately 42% about the initial amount. These changes are correlated with changes in the photomagnetic properties.
Second harmonic generation in a GaP waveguide
Authors: van der Ziel J. P. , Mikulyak R. M. , Cho A. Y.
Published: February 2003

Waveguiding of 1.0642-μm radiation and nonphase-matched second harmonic generation have been observed in a 200-Å-thick GaP waveguide grown by molecular beam epitaxy on a (111) -oriented CaF2 substrate.
Self-quenching in semiconductor lasers and its applications in optical memory readout
Authors: Seko A. , Mitsuhashi Y. , Morikawa T. , Shimada J. , Sakurai K.
Published: February 2003

The laser oscillation in a double-heterostructure GaAlAs laser is quenched by its own output laser beam. Application of this effect in optical memory readout is suggested and demonstrated.
Room-temperature operation of low-threshold separate-confinement heterostructure injection laser with distributed feedback
Authors: Casey H. C. , Somekh S. , Ilegems M.
Published: February 2003

Separate-confinement heterostructure injection lasers with periodic corrugations in the optical cavity were prepared by a hybrid liquid phase epitaxy (LPE) and molecular beam epitaxy (MBE) growth process. The N-Al0.3Ga0.7As, N-Al0.12Ga0.88As, p-GaAs active layer, and P-Al0.12Ga0.88As layers were grown by LPE, a 0.3748-μm periodic corrugation was ion milled into the P-Al0.12Ga0.88As layer, and then the P-Al0.3Ga0.7As and p-GaAs top layers were grown over the corrugation by MBE. The temperature dependence of the lasing wavelength between 12.6 and 24.8 °C demonstrated the behavior expected for a distributed-feedback laser. The threshold current density was 2.2 kA/cm2 at room temperature.
Hot-carrier instability in IGFET’s
Authors: Abbas S. A. , Dockerty R. C.
Published: February 2003

Injection of hot carriers from the channel region into the gate insulator of an IGFET imposes design constraints on the device dimensions and operating voltages. A fraction of the injected charge is trapped in the gate dielectric, and an undesirable shift in the operating characteristics results. The magnitude of the shift is related to the device dimensions, operating voltages, and gate dielectric.
Stimulated emission at 281.8 nm from XeBr
Authors: Searles S. K. , Hart G. A.
Published: February 2003

Xenon with 0.10–4% Br2 was excited by an e-beam device over the range 10–3000 Torr. Stimulated emission was observed on the transition XeBr*→Xe+Br+hν (281.8 nm). Proof of laser emission and mechanistic details are discussed.