bluuebunny/crossref_metadata_2025 huggingface dataset:
Electron paramagnetic resonance identification of the phosphorus antisite in electron-irradiated InP
Authors: Kennedy T. A. , Wilsey N. D.
Published: February 2003

A new electron paramagnetic resonance spectrum observed in electron-irradiated InP is analyzed and attributed to the PIn antisite defect. The spectrum has an isotropic g value of 1.992±0.008 and a central hyperfine coupling of 0.092±0.005 cm−1 with a 100%, I= 1/2 nucleus. Irradiation conditions for the observation of PIn are described and comparison is made to antisites in GaP and GaAs.
Dispersion and polarization dependence of mobile carrier optical nonlinearities
Authors: Rustagi K. C.
Published: February 2003

Based on the author’s earlier work, it is shown that the proper inclusion of carrier scattering should strongly modify the frequency and polarization dependence of optical nonlinearities due to mobile carriers in semiconductors. When the momentum relaxation is much faster than the energy relaxation, the intensity dependent refractive index is enhanced, the induced birefringence becomes a sharp function of the difference frequency ωa−ωb, and a collision induced stimulated Raman effect becomes important.
Single-ion recombination lasers in CO2 laser-vaporized target material
Authors: Wood O. R. , Macklin J. J. , Silfvast W. T.
Published: February 2003

Fifteen recombination lasers have been produced in the ionic species of nine elements by focusing eight transversely excited atmospheric pressure CO2 laser beams onto targets of these materials to produce an elongated gain region in the vaporized plasmas. The results include the first lasers in ionized species and also the first visible lasers excited by this process.
Dependence of astigmatism, far-field pattern, and spectral envelope width on active layer thickness of gain guided lasers with narrow stripe geometry
Authors: Mamine Takayoshi
Published: February 2003

The effects of active layer thickness on the astigmatism, the angle of far-field pattern width parallel to the junction, and the spectral envelope width of a gain guided laser with a narrow stripe geometry have been investigated analytically and experimentally. It is concluded that a large level of astigmatism, a narrow far-field pattern width, and a rapid convergence of the spectral envelope width are inherent to the gain guided lasers with thin active layers.
High resolution photothermal laser probe
Authors: Williams C. C.
Published: February 2003

At frequencies near 1 GHz, the acoustic wavelength in argon gas becomes half that of visible light, making possible collinear Bragg scattering of laser light by the sound. This acousto-optic interaction has been used to detect photothermally generated acoustic power at the surface of solids. This new technique provides a noncontacting probe for the detection of 100–1000-Å thermal waves with optical resolution. The essential features of the theory behind this new photothermal probe are presented along with a description of the experimental implementation. High resolution images of implanted silicon are included which clearly demonstrate the sensitivity of the probe to variations in the thermal characteristics of solids.
Comparison of XeF2 and F-atom reactions with Si and SiO2
Authors: Ibbotson Dale E. , Flamm Daniel L. , Mucha John A. , Donnelly Vincent M.
Published: February 2003

Silicon gasification by XeF2 is compared with F-atom etching under conditions typical of those used in plasma etching. Temperatures ranged from −17 to 360 °C and XeF2 pressures were between 0.05 and 2 Torr. Silicon etching by XeF2 shows a sharply different etch rate/temperature dependence than the Si/F or Si/F2 reaction systems; there is no detectable reaction between XeF2 and SiO2 in contrast to the F-atom/SiO2 system. These data indicate that physisorption can limit silicon etching by XeF2 and show that basic studies which use XeF2 as a model compound for the etching of silicon and SiO2 by F atoms should be interpreted with caution.
Noncontact thermal-wave imaging of subsurface structure with infrared detection
Authors: Ermert H. , Dacol F. H. , Melcher R. L. , Baumann T.
Published: February 2003

A noncontact thermal imaging system using infrared detection is described. The system uses a chopped and scanned electron beam as a heat source to produce a temperature pattern on the surface of the sample. The resulting thermal radiation is detected and used for numerical image reconstruction of the sample’s subsurface structure.
19.1% efficient silicon solar cell
Authors: Green M. A. , Blakers A. W. , Shi Jiqun , Keller E. M. , Wenham S. R.
Published: February 2003

Substantial improvements in silicon solar cell performance are reported. These improvements have been obtained primarily by improved cell open circuit voltage obtained by improved passivation of the cell emitter region. Careful attention to optical design and to the minimization of parasitic resistances has also resulted in the demonstration of short circuit current densities and fill factors comparable to the best values reported for silicon.
Optically induced electron spin resonance and spin-dependent recombination in Si/SiO2
Authors: Henderson B.
Published: February 2003

In state-of-the-art Si/SiO2 wafers the concentration of paramagnetic interface states (≂1010 cm−2) is almost too low to be detected by electron spin resonance (ESR). This letter describes experiments which show that the ESR signal of singly occupied dangling bond defects (so called Pb centers) may be considerably enhanced by optical irradiation in the wavelength region 650–1050 nm. Furthermore, the Pb center resonance may be observed as a change in the photocurrent produced by optical excitation in this region. Such spin-dependent photoconductivity results from the spin selection rules for electron-hole recombination at the defect. This observation demonstrates that the Pb center levels in Si/SiO2 wafers act as both recombination centers and interface states.
CdTe films on (001) GaAs:Cr by molecular beam epitaxy
Authors: Mar H. A. , Chee K. T. , Salansky N.
Published: February 2003

CdTe films grown by molecular beam epitaxy on a (001) GaAs with a 14% lattice mismatch were found to be a very good crystalline quality. The films were found by reflection high-energy electron diffraction analysis to be oriented (111) parallel to the surface of the (001) GaAs. Further, the [112̄] azimuth of CdTe and the [110] of GaAs were aligned. Photoluminescence studies suggest that the films are of high crystalline quality but peaks associated with impurities are observed in the spectra. The optimum growth temperature is about 250 °C.
Photoluminescence characterization of molecular beam epitaxial GaAs grown using cracked AsH3
Authors: Skromme B. J. , Stillman G. E. , Calawa A. R. , Metze G. M.
Published: February 2003

High purity undoped molecular beam epitaxial GaAs layers grown using cracked AsH3 as the As source have been characterized by low-temperature (1.7–20 K) photoluminescence measurements. The dominant residual acceptor was found to be either Mg or Be (which cannot be distinguished by this technique), with smaller amounts of C, Si, Ge, Sn, and Mn also present. The incorporation of residual amphoteric impurities depends strongly on the As to Ga flux ratio. The ‘‘defect’’-related luminescence characteristic of material grown with a solid As source was not detected. A sample grown in the same system using solid As showed only C acceptors but did produce defect luminescence.
Studies of a-Si:H growth mechanism by Rutherford recoil measurement of H and D in films prepared from SiH4-D2 and SiD4-H2
Authors: Yatsurugi Yoshifumi , Kuboi Osamu , Hashimoto Masanori , Nagai Hisao , Aratani Michi , Yanokura Minoru , Kohno Isao , Nozaki Tadashi
Published: February 2003

a-Si:H films were prepared by rf glow discharge in SiH4-D2 or SiD4-H2 mixtures and analyzed for H and D by Rutherford forward recoil measurement in order to study its growth mechanism. In a low power rf discharge, more H atoms than D atoms were incorporated in the a-Si:H film even in the SiH4(1 vol)-D2(4 vol) mixture. With increase in the rf power, the H to D ratio in the film approaches the ratio in the gas for rf power ranges relatively high in our experiment, but is usual in practical production of a-Si:H. The two ratios were found to be almost equal, independent of the gas composition.
Josephson current distribution in two-dimensional Josephson tunnel junctions
Authors: Lhota James R. , Scheuermann M. , Kuo P. K. , Chen J. T.
Published: February 2003

A laser scanning technique has been used to obtain the Josephson current distributions in two-dimensional Josephson tunnel junctions. For zero external magnetic field, current distributions of cross-type junctions using symmetric and asymmetric feed configurations are found to be qualitatively different from the published theoretical results. In addition the current distributions in various magnetic fields are also presented.
Transversely excited N2O sequence band laser
Authors: Hara Hiroshi , Whitney W. T.
Published: February 2003

Sequence band operation of a transversely excited nitrous oxide laser is reported for the first time. The sequence laser could be tuned to each V-R line from R(25) to R(14) and from P(14) to P(26) in the 10.7-μm band. Output energies were 10 μJ–1 mJ. Improved stability of the discharge at high specific energy loading and use of an intracavity hot cell made sequence band oscillation possible.
Growth of single crystal SrF2(001)/GaAs(001) structures by molecular beam epitaxy
Authors: Sullivan P. W.
Published: February 2003

Epitaxial SrF2 layers were grown onto GaAs (001) at T>250 °C by molecular beam epitaxy. The dominant growth mechanism appears to be by three-dimensional island growth although significant ordering of the surface occurs on annealing the layers at T>400 °C. Growth of epitaxial GaAs (001) at 540 °C by molecular beam epitaxy onto the SrF2 films has also been demonstrated. The results suggest that stacked, single crystal, alternating layers of GaAs (001) and SrF2 (001) should be amenable to growth by molecular beam epitaxy.
Role of carbon in hydrogenated amorphous silicon solar cell degradation
Authors: Crandall R. S. , Carlson D. E. , Catalano A. , Weakliem H. A.
Published: February 2003

Experiments using a combination of capacitance and photovoltaic transient spectroscopy on hydrogenated amorphous silicon solar cells demonstrate that carbon produces a metastable defect with characteristic energy and emission time. This defect is involved in solar cell degradation.
Structural characterization by transmission electron microscopy of silicon grown over submicrometer-period gratings of deposited tungsten
Authors: Vojak B. A. , Rathman D. D. , Burns J. A. , Cabral S. M. , Efremow N. N.
Published: February 2003

The Si overgrowth of deposited W gratings, which is the most critical step in the fabrication of the overgrown version of the Si permeable base transistor, has been characterized by transmission electron microscopy. At the high temperatures (>1000 °C) normally required for the growth of single-crystal Si, the W grating reacts with both the surrounding and depositing Si to form WSi2. Despite this conversion, conventional vapor phase epitaxial techniques can be used to overgrow the grating with a single-crystal Si layer. The overgrown layer contains a low density of observed crystal defects. The fabrication procedure used for successful overgrowth and the quality of the overgrown layer are discussed.
Influence of orientation dependent growth kinetics on the performance of InGaAsP buried crescent lasers
Authors: Temkin H. , Logan R. A. , Van der Ziel J. P.
Published: February 2003

The growth reproducibility of the separate optical confinement buried crescent laser has been studied in the wavelength region of 1.3<λ≤1.62 μm. The performance and yield of λ=1.55 μm lasers were found to be impaired by the competition between the (100) and (111) growth habits leading to the perturbed growth of the active layer. These results are discussed in terms of the crystallographic direction dependence of the liquid-solid distribution coefficient.
4.4-μm cascade 13C 16O2 laser
Authors: Johnson R. P. , Cornelison D. , Buzcek C. J.
Published: February 2003

An in-cavity hot 13C 16O2 cell is used to obtain a 4.4-μm lasing from a cascade process in a sealed off 13C 16O2 laser. The 4.4-μm laser is tunable and operates on the P branch (near 4.44 μm) and the R branch (near 4.39 μm) of the ([10°1]I–[10°0]I) band of 13C 16O2. The laser is mechanically Q switched producing peak powers in excess of 10 W with repetition rates greater than 500 Hz.
Nonlinear prism coupler
Authors: Liao C. , Stegeman G. I.
Published: February 2003

The problem of coupling an external radiation field into a thin-film waveguide characterized by a power-dependent refractive index has been investigated theoretically. The optimum coupling efficiency is found to decrease with increasing power.
Ga0.47In0.53As/InP multiquantum well heterostructure lasers grown by molecular beam epitaxy operating at 1.53 μm
Authors: Tsang W. T.
Published: February 2003

Current injection Ga0.47In0.53As/InP multiquantum well heterostructure lasers operating at 1.53 μm have been successfully prepared by molecular beam epitaxy. These lasers consist of four ∼70 Å Ga0.47In0.53As wells and three ∼150 Å InP barriers. The threshold current density is 2.7 kA/cm2. In the temperature range of 10–75 °C, the threshold-temperature dependence can be described closely by a single temperature dependence coefficient T0. The measured T0 is 45 K. No significant improvement in T0 is observed in these multiquantum well lasers over conventional double-heterostructure lasers operating also at 1.5 μm.
Microstructure-independent acoustoelastic measurement of stress
Authors: Thompson R. B. , Smith J. F. , Lee S. S.
Published: February 2003

Measurements are reported of the velocities of horizontally polarized shear waves (fundamental mode) propagating in the plane of aluminum plates under tensile loads applied parallel to the rolling direction. In agreement with the predictions of previous theories, the applied stress is found to be predicted by the expression 2C(ΔV/V), where C is the appropriate second-order shear elastic constant and ΔV/V is the fractional difference in velocities of waves propagating parallel and perpendicular to the load. The data show that, whereas the individual velocities are strongly influenced by microstructure, the stress prediction based on their difference is not. Included are results illustrating the effects of preferred grain orientation and plastic deformation.
Growth of (100)CdTe films of high structural perfection on (100)GaAs substrates by molecular beam epitaxy
Authors: Bicknell R. N. , Yanka R. W. , Giles N. C. , Schetzina J. F. , Magee T. J. , Leung C. , Kawayoshi H.
Published: February 2003

Growth of epitaxial (100) CdTe films on (100) GaAs substrates by molecular beam epitaxy is discussed. X-ray diffraction, UV reflectance, photoluminescence, and transmission electron microscopy techniques were employed to characterize the film specimens. The high structural perfection of the layers was evidenced by line dislocation densities of ≤104/cm2 at the free surface of films ≂6.6 μm thick and by measurable excitonic photoluminescence (∼1.504 eV) at room temperature. The CdTe epilayers were smooth and mirrorlike in appearance.
Capture and tunnel emission of electrons by deep levels in ultrathin nitrided oxides on silicon
Authors: Chang Shuo-Tung , Johnson N. M. , Lyon S. A.
Published: February 2003

Electron injection into ultrathin nitrided oxides on silicon reveals both high densities of electronic defects, which readily capture electrons, and efficient tunnel emission of trapped charge. High-temperature nitridation of thermally grown oxides was verified with Auger depth profiling. In 11–17-nm-thick nitrided oxides, the electron trap density is ≥1×1019 cm−3 as determined from saturated charge accumulation, the majority of the traps are energetically situated more than 2 eV below the conduction band as determined by post-injection anneals up to 300 °C, and the capture cross section is of the order of 10−14 cm2 as estimated from the trapping kinetics. Complete extraction of trapped charge is achieved in the thinnest films (e.g., ≤11 nm thick), and the tunnel emission mechanism is evidenced by the independence of the discharge time on temperature. Implications of the above findings for applications of ultrathin nitrided oxides in very large scale integration and for their low sensitivity to ionizing radiation are discussed.
Identification of the residual acceptors in undoped high purity InP
Authors: Skromme B. J. , Stillman G. E. , Oberstar J. D. , Chan S. S.
Published: February 2003

The ionization energies of C, Be, and Mg acceptors in InP have been determined by means of low-temperature (1.7–20 K) photoluminescence measurements on high purity epitaxial and bulk samples which have been implanted with low (5×109–5×1011 cm−2) doses of those impurities. The measured values are 44.6±0.3, 41.3±0.3, and 41.0±0.3 meV, respectively. A comparison with the ionization energies of the residual acceptors in liquid phase epitaxial (LPE), PH3-vapor phase epitaxial, liquid encapsulated Czochralski, and polycrystalline samples indicates that C is almost never present as a residual acceptor in undoped InP. The ionization energy of the main residual acceptor in the LPE samples matches that of both Mg and Be.
Effects of UV irradiation on the inverted surface layer in semiconductor-insulator-semiconductor devices
Authors: Ghosh Amal K. , Haberman Joel I. , Feng Tom
Published: February 2003

Irradiating semiconductor-insulator-semiconductor devices with 3650 Å light increases the J0 associated with the minority-carrier injection/diffusion current, resulting in a concomitant decrease in Voc. This increase in J0 is attributed to a decrease in carrier lifetime in the inverted surface layer as a result of UV irradiation.
Monolithic integration of an AlGaAs/GaAs multiquantum well laser and GaAs metal-semiconductor field-effect transistors on a semi-insulating GaAs substrate by molecular beam epitaxy
Authors: Sanada T. , Yamakoshi S. , Wada O. , Fujii T. , Sakurai T. , Sasaki M.
Published: February 2003

AlGaAs/GaAs multiquantum well lasers and GaAs metal-semiconductor field-effect transistors have been monolithically integrated on a semi-insulating GaAs substrate by using molecular beam epitaxy. This integrated laser has exhibited cw operation with the low threshold current of 20 mA at room temperature. The laser/field-effect transistor (FET) characteristics, such as a linear control of laser output power by changing the FET gate voltage, have been confirmed. A conversion ratio of laser output power to FET gate voltage has been measured to be as high as 3.3 mW/V. Rise and fall times of 1 ns have been demonstrated.
Identification of oxygen-related midgap level in GaAs
Authors: Lagowski J. , Lin D. G. , Aoyama T. , Gatos H. C.
Published: February 2003

An oxygen-related deep level ELO was identified in GaAs employing Bridgman-grown crystals with controlled oxygen doping. The activation energy (825±5 meV) of ELO is almost the same as that of the dominant midgap level: EL2 (815±2 meV). This fact impedes the identification of ELO by standard deep level transient spectroscopy. However, we found that the electron capture cross section of ELO is about four times greater than that of EL2. This characteristic served as the basis for the separation and quantitative investigation of ELO employing detailed capacitance transient measurements in conjunction with reference measurements on crystals grown without oxygen doping and containing only EL2.
Beryllium implantation doping of InGaAs
Authors: Tell B. , Leheny R. F. , Liao A. S. H. , Bridges T. J. , Burkhardt E. G. , Chang T. Y. , Beebe E. D.
Published: February 2003

Ion implantation doping of Be acceptors in n-In0.53Ga0.47As is reported. A significant improvement in peak concentration, depth control, and solubility is achieved with rapid (30 s) thermal anneals compared to conventional 15-min furnace anneals, resulting in p-n junction depths less than 1 μm with peak acceptor concentrations greater than 1018 cm−3. Electrical profiles and p-n junction characteristics are presented.
Anodic sulfide films on Hg1−xCdxTe
Authors: Nemirovsky Y. , Burstein L.
Published: February 2003

A novel anodic sulfidization process for forming native sulfide films on Hg1−xCdxTe is described. In the new process native sulfide films rather than native oxides terminate the lattice and passivate the surface. The results of Auger electron spectroscopy analysis indicate that native homogeneous CdS films are formed with an abrupt interfacial transition. The measured capacitance-voltage characteristics of metal-insulator-semiconductor devices indicate that the films have a low negative fixed surface charge density of the order of –1×1011 e cm−2 and a relatively low concentration of fast surface charge density. The native sulfide films leave the surface of p-type Hg1−xCdxTe practically at flat band and in this respect are superior to native oxide films which invert the surface of p-type material. The new surface passivation is in particular suitable for photovoltaic diodes implemented on p-type Hg1−xCdxTe.
Line-tunable oscillation of a cw NH3 laser from 10.7 to 13.3 μm
Authors: Rolland C. , Reid J. , Garside B. K.
Published: February 2003

A cw CO2 laser operating on the R(30) 9-μm transition is down shifted by 180 MHz in a pair of acousto-optic modulators, and used to optically pump sR(5,0) transition of NH3 at line center. Vibrational inversion is created in the ν2 mode, and cw oscillation is observed on 20 different NH3 lines, spanning the region between 10.7 and 13.3 μm. Single line output powers as high as 760 mW were measured in a waveguide cavity. The operation of this laser is explained using a simple thermalization model, and several potential applications are discussed.
Coupling mechanism of gain-guided integrated semiconductor laser arrays
Authors: Kapon E. , Lindsey C. , Katz J. , Margalit S. , Yariv A.
Published: February 2003

It is shown that a gain-guided laser array couples via propagating fields rather than the evanescent mode coupling typically responsible for directional coupling in passive (directional couplers) and active (laser array) devices. We show that these phase-locked modes exhibit an interference pattern, in the junction plane, which arises from the curvature of the phase fronts of optical fields of the interacting lasers. The experimental results are interpreted with the aid of a simple theoretical model, and the effect of the observed mode pattern on the coupling of gain-guided lasers is discussed.
Improvement of crystal homogeneities in liquid-encapsulated Czochralski grown, semi-insulating GaAs by heat treatment
Authors: Miyazawa Shintaro , Honda Takashi , Ishii Yasunobu , Ishida Satoru
Published: February 2003

Crystal homogeneities in liquid-encapsulated Czochralski grown, semi-insulating GaAs (100) wafers were evidently improved by annealing at 800 °C for more than 12 h. The improvement was confirmed by observing cathodoluminescence intensity line scanning profile and by measuring field-effect transistor (FET) threshold voltage standard deviation σVth. σVth for 14-h and 18-h annealed/polished wafers exhibited about one-half that for a nonannealed wafer. Direct evidence of the improvement was also obtained by measuring dislocation effect on FET threshold voltage.
Power gain of a SQUID amplifier
Authors: McDonald D. G.
Published: February 2003

The power gain of a dc superconducting quantum interference device (SQUID) amplifier, with tuned input and output circuits, is computed as a function of the current and magnetic biases. A gain of 20300 is found at 1.5 GHz and 3470 at 3.0 GHz, implying a frequency dependence to the gain of approximately ω−2. The gain, as derived from the resistively shunted junction model, is compared with the gain of a simplified model based on the dc magnetic response Vφ. This comparison shows that the Vφ description of the SQUID can lead to large errors.
Transport properties of composites having the CsCl structure
Authors: McPhedran R. C.
Published: February 2003

A formulation is presented for the problem of calculating the effective transport coefficient of a three-phase composite material, having two phases of spherical inclusions arranged in the CsCl structure in a matrix material. A formula is given for the effective transport coefficient ε taking into account dipole and octupole terms in multipole field expansions. The flexibility of the formula in modelling the behavior of ε over a wide range of volume fractions is demonstrated.
‘‘Buffer-layer’’ technique for the growth of single crystal SiC on Si
Authors: Addamiano A. , Sprague J. A.
Published: February 2003

The nature of the buffer layers needed for the single crystal deposition of cubic SiC on Si substrates was studied. It is concluded that the buffer layer is a stressed monocrystalline layer of cubic SiC.
SiOxNy capped annealing for Si-implanted GaAs
Authors: Kuzuhara M. , Kohzu H.
Published: February 2003

Si-implanted GaAs was successfully annealed with silicon oxynitride (SiOxNy) encapsulant. By using SiOxNy encapsulant with about 1.75 refractive index, a maximum electrical activation of 87%, which is 30–50% higher than that obtained after SiO2 or Si3N4 capped annealing, was achieved on Si-implanted GaAs (5×1012 cm−2, 100 keV). In addition, electrical activation after SiOxNy capped annealing remains constant against the variation of film thickness up to 2300 Å, indicating minimized interfacial stress between SiOxNy film and GaAs substrate. A maximum carrier concentration of 2.5×1018 cm−3, which is the highest value ever reported on Si-implanted GaAs, was obtained after SiOxNy capped annealing for 7×1013 cm−2 dose. The controlled amount of Ga outdiffusion in combination with the reduced interfacial stress is considered to be responsible for this high electrical activation.
Some characteristics of the GaAs/GaAlAs graded-index separate-confinement heterostructure quantum well laser structure
Authors: Hersee S. D. , de Cremoux B. , Duchemin J. P.
Published: February 2003

We describe the characteristics of graded-index separate-confinement heterostructure (GRIN-SCH) quantum well laser structures for a wide range of quantum well thickness and graded layer composition. It was deduced that the ‘‘GRIN’’ region enhances carrier confinement and assists the thermalization of carriers into the quantum well. A maximum value of T0 of 190 K was measured for these single quantum well lasers.
Improved linearity and kink criteria for 1.3-μm InGaAsP-InP channeled substrate buried heterostructure lasers
Authors: Dutta N. K. , Wilt D. P. , Besomi P. , Dautremont-Smith W. C. , Wright P. D. , Nelson R. J.
Published: February 2003

Nonlinearities or kinks in the light-current characteristics of channeled substrate buried heterostructure lasers are associated with higher order transverse mode transition and lateral mode movement. The active area has been reduced to stabilize the transverse mode. Fundamental mode operation up to high powers (24 mW/facet) has been obtained in devices with threshold current as low as 15 mA. Measurements and calculations are presented which show that nonlinearities occur at higher output power in lasers with reduced active area.
Characterization of laser annealed InP with ellipsometry and Hall effect measurement
Authors: Fremunt R. , Hirayama Y. , Arai F. , Sugano T.
Published: February 2003

Indium phosphide layers into which sulphur ions were implanted at room temperature in the dose range of 5×1013–1×1015 cm−2 were annealed with continuous wave (cw) Nd:yttrium aluminum garnet (YAG) laser beam in double scan with the power density from 1.8 to 5.4×104 W cm−2 at a dwell time of 3.6 ms. Following annealing the samples were characterized by ellipsometry and the electrical activity of implanted ions was assessed by Van der Pauw type Hall measurements. At high doses, electrical activity over 20% and electron mobility of about 1500 cm2/V s were obtained, but electrical properties were poor at low doses. It is assumed that the effect of activated impurities is compensated by defects, which were induced by cw Nd:YAG laser annealing, to a large extent.
Inelastic tunneling characteristics of AlAs/GaAs heterojunctions
Authors: Collins R. T. , Lambe J. , McGill T. C. , Burnham R. D.
Published: February 2003

We report the first observation of inelastic tunneling in electronic transport perpendicular to a thin AlAs layer sandwiched between two GaAs layers. Temperature dependent I–V, first derivative (dI/dV), and second derivative (d2I/dV2) measurements were made on AlAs/GaAs double heterojunctions for a range of AlAs layer thicknesses and dopings. For p-type AlAs barriers current transport at 4.2 K was due to tunneling, and reproducible structure was seen in the second derivative spectrum. This structure was associated with the inelastic excitation of AlAs optical phonons and with a density-of-states effect caused by optical phonon-electron coupling in the GaAs. A different second derivative spectrum which also exhibited reproducible structure was obtained for n-type AlAs layers. Several possible explanations for these differences are proposed.
Spatially resolved measurement of substitutional dopant concentrations in semiconductors
Authors: Pennycook S. J. , Narayan J. , Holland O. W.
Published: February 2003

It is shown that a simple ratio technique based on the electron channeling phenomenon can be used to measure substitutional fractions of dopants in submicron-sized regions of semiconductors. Samples were made from 121Sb+ implanted Si, solid-phase-epitaxially regrown, and analyzed by ion channeling. One sample was sequentially annealed so as to precipitate out various fractions of the dopant in excess of the solubility limit. In the fully annealed sample electron channeling measurements could quantitatively determine the fraction of Sb in precipitate form since it was randomly located with respect to the matrix. In the partially annealed sample electron channeling indicated a larger nonsubstitutional fraction than could be accounted for by observed precipitates.
Rapid thermal annealing of boron-implanted silicon using an ultrahigh power arc lamp
Authors: Hodgson R. T. , Deline V. R. , Mader S. , Gelpey J. C.
Published: February 2003

We have used an ultrahigh powered, 100-kW vortex cooled arc lamp to anneal 75-mm-diam 〈100〉 silicon wafers implanted with various doses of 50-keV B+ and BF+2 ions. Sheet resistivity measurements, secondary ion mass spectrometry, and transmission electron microscopy have been used to characterize the annealed wafers. Standard diffusion coefficients predict little dopant movement in the temperature (∼1200 °C) and time (∼1 s) region we studied. However, boron atoms which have been channeled relatively deep into the silicon and left in interstitial positions move ∼100 nm in ∼1 s at low temperatures, then stop. We presume that they encounter a vacancy and become substitutional. The dopant diffusion rate then is close to equilibrium values, and there is little measurable movement between 900 and 1250 °C. A 3-s lamp cycle with maximum wafer temperature 1230 °C is sufficient to fully activate a 1014 cm−2 BF+2 implant and leave the material with no extended defects. The dopant half-width and junction depth are 50 and 250 nm for the as-implanted sample, and 90 and 340 nm for the annealed sample.
Strained-layer quantum-well injection laser
Authors: Laidig W. D. , Caldwell P. J. , Lin Y. F. , Peng C. K.
Published: February 2003

Data are presented demonstrating room-temperature operation of a strained-layer quantum-well injection laser. The laser structure, grown by molecular beam epitaxy, consists of an active region with three InxGa1−xAs (x∼0.35) quantum wells (LZ ∼40 Å) separated by two GaAs barriers (LB ∼30 Å). These layers are centered in a larger GaAs collection/confinement region (LZ ∼1600 Å) bounded by AlyGa1−yAs ( y∼0.45) cladding layers. The lasers operate at λ∼1.0 μm with greater than 4-mW optical power output/facet under pulsed conditions at 300 K. Threshold current densities between 1000 and 2000 A/cm2 are obtained.
Contribution of oscillating mass transfer to the photoacoustic effect
Authors: Korpiun P.
Published: February 2003

In a gas-microphone cell absorption of modulated light causes oscillating transport of heat and of mass as well. The transport of mass is described by the diffusion equation. The concentration of substance from sample or sorbate at the sample to gas boundary is obtained from the vapor pressure. Introduction of an average molar concentration variation leads to a pressure variation. Results of calculations can explain recently measured data very well. For water at 40 °C oscillating mass transfer contributes the same amount to pressure variation as the heat wave.
Semitransparent silicide electrodes utilizing interaction between hydrogenated amorphous silicon and metals
Authors: Seki K. , Yamamoto H. , Sasano A. , Tsukada T.
Published: February 2003

Thin silicide layers are found to be formed through solid state reaction between hydrogenated amorphous silicon (a-Si:H) and metals. The method of formation of the silicide layer is very simple: deposition of metal, annealing, and etching of the residual metal layer. The reaction kinetics and properties of this layer are described. The thickness of this silicide layer is estimated to be less than 100 Å. Accordingly, it can be used as the semitransparent electrode in a-Si:H photodiodes. This layer is more chemically stable than such conventional transparent semiconductive oxides as indium tin oxide (ITO). Photodiodes using this semitransparent electrode have as good optical and electrical characteristics as conventional a-Si:H photodiodes using ITO.
Picosecond degenerate four-wave mixing through orientation and concentration gratings in GaAs
Authors: Oudar J. L. , Abram I. , Minot C.
Published: February 2003

We report the observation of degenerate four-wave mixing in GaAs above the band gap, using tunable picosecond pulses in the 1.53–1.61-eV region. A very fast contribution due to orientational gratings of electron-hole pairs is isolated with orthogonally polarized beams. This is observed for incident intensities down to 5 MW/cm2, i.e., two orders of magnitude lower than recently reported for germanium. Even at this relatively low power density, higher order effects are important, as evidenced by the power dependence of the conversion efficiency.
Reverse bias and heat treatment to improve performance of a-Si solar cells
Authors: Swartz G. A.
Published: February 2003

Amorphous silicon solar cells deposited on tin oxide coated glass with an amorphous silicon carbide  p+ front contact layer were subjected to a reverse potential bias while at elevated temperatures. The bias-anneal treatment improved measured values of open circuit voltage, fill factor, and overall efficiency. The treatment increases efficiency by as much as 18%. The improvement in cell performance appears to be related to an increase in the  μτ product and possibly an increase in the ionized dopant concentration of one or both contact layers.
Effects of leakage current on deep level transient spectroscopy
Authors: Chen M. C. , Lang D. V. , Dautremont-Smith W. C. , Sergent A. M. , Harbison J. P.
Published: February 2003

A tunnel metal-insulator-semiconductor capacitor has been studied by deep level transient spectroscopy (DLTS) technique to demonstrate, along with computer simulation, that the presence of leakage current can drastically affect the DLTS spectra of a broad distribution of states. This leakage current causes carrier capture which competes with the thermal emission to change the trap occupancy. If not recognized and corrected, leakage effects can lead to serious misinterpretations of DLTS results.
Line-sampling multiframe stroboscopic technique for dynamic observation of periodic phenomena at low frequencies
Authors: Shimizu R. , Ikuta T.
Published: February 2003

A new type of stroboscopic observation technique is described here, which enables dynamic observation of periodic phenomena driven at such low frequency as commercial frequency (50 or 60 Hz). This technique is based on the use of ‘‘scan-line sampling’’ instead of the scan-point sampling used in conventional stroboscopic observations, and on displaying plural scan-line stroboscopic images corresponding to different phase values of the driving field on a CRT in tens of seconds. As an application, dynamic observation of magnetic domains in a Fe-Si (4%) alloy driven by a magnetic field of 60 Hz is demonstrated using a scanning electron microscope.
Carrier dependence of the radiative coefficient in III-V semiconductor light sources
Authors: Su C. B. , Olshansky R. , Manning J. , Powazinik W.
Published: February 2003

In this letter the carrier dependence of the radiative bimolecular coefficients obtained from differential carrier lifetime measurements is reported. The bimolecular coefficient B(n) decreases significantly with carrier density. It is found that B(n) is well approximated by B(n)≂B0−B1n, with B1/B0=(1.1±0.2)×10−19 cm3 for GaAlAs and (1.6±0.2)×10−19 cm3 for 1.3 μm InGaAsP. This effect has a strong influence on the spontaneous emission efficiency in both InGaAsP and GaAlAs light sources.
Differential effective medium theory of sedimentary rocks
Authors: Sheng Ping , Callegari A. J.
Published: February 2003

We show that both the electrical and acoustic properties of fluid-saturated sedimentary rocks can be described within the unified framework of differential effective medium theory. Calculations based on the differential effective medium picture of rock microstructure yield predictions of sonic travel times and acoustic attenuation in good agreement with experimental data. In particular, the theory shows that the large frequency peak in attenuation and its associated velocity dispersion observed in sandstones are characteristic of a composite system containing fluid-filled microcracks.
Experimental investigation of a magnetic gate as a multimegampere, vacuum opening switch
Authors: Kania D. R. , Jones L. A. , Zimmermann E. L. , Veeser L. R. , Trainor R. J.
Published: February 2003

We report on the first experiments to demonstrate the vacuum operation of a magnetic gate opening switch. Currents greater than 1 MA have been transferred in approximately 1 μs. A model has been developed to describe the switch’s operation. The model and the experimental data are in excellent agreement.
Arsenic out-diffusion during TiSi2 formation
Authors: Amano Jun , Merchant P. , Koch Tim
Published: February 2003

The behavior of implanted As atoms during high-temperature (800–900 °C) TiSi2 formation was investigated by helium backscattering. A significant As loss was observed during TiSi2 formation by vacuum furnace annealing. The main factors influencing the As loss were the initial As profiles and Ti film thickness. Most of the As loss was caused by rapid As out-diffusion through the TiSi2 layer; the remaining As atoms were only observed in the Si substrate after TiSi2 formation. As long as the As distribution was deeper than the TiSi2 layer, the loss of As atoms was kept to a minimum. Careful selection of the As implantation energy and the Ti film thickness can achieve high As concentration at the TiSi2/Si interface.
Direct confirmation of the conduction-band lineup in the CuInSe2-CdS heterojunction solar cell
Authors: Turowski M. , Kelly M. K. , Margaritondo G. , Tomlinson R. D.
Published: February 2003

We applied to the CuInSe2-CdS system the Katnani–Margaritondo rule for estimating heterojunction-band discontinuities from photoemission measurements. We found that the CuInSe2 conduction-band edge is 0.2 eV above the CdS conduction-band edge. This band-edge lineup explains the efficiency of p-CuInSe2/n-CdS solar cells.
High quality Hg1−xCdxTe epitaxial layers by the organometallic process
Authors: Ghandhi Sorab K. , Bhat Ishwara
Published: February 2003

An organometallic process for the epitaxial growth of Hg1−xCdxTe is described in this letter. This process involves the simultaneous pyrolysis of dimethylcadmium and diethyltelluride in mercury vapor at 415 °C, using hydrogen as the carrier gas. It is shown this process results in device quality layers of uniform composition. Layers with x=0.17 exhibited n-type conduction, with an approximate carrier concentration of 3.8×1015 cm−3, and a Hall mobility of 2.45×105 cm2/Vs at 77 K. Thus, they are comparable to the best grown by liquid phase epitaxy. A p-type layer, with anomalous electrical characteristics, has also been described in this letter. Reasons for these anomalous characteristics are outlined briefly.
Direct evidence of arsenic clustering in high dose arsenic-implanted silicon
Authors: Wu N. R. , Sadana D. K. , Washburn J.
Published: February 2003

High dose (5–7.5×1015 cm−2) arsenic implantation was conducted in the energy range 50–120 keV into three types of (100)Si substrates: (i) bare Si, (ii) with a thermally grown screen oxide (775 Å), and (iii) preamorphized surface layer produced by self-implantation. The substrates were subsequently furnace annealed at 600 °C in N2. Cross-section transmission electron microscopy (XTEM) revealed that in all cases discrete layers of As related clusters and small dislocation loops occurred at depths matching the projected ranges of As into the Si substrates and original amorphous/crystalline interfaces respectively. The atomic profiles of As obtained by secondary ion mass spectrometry (SIMS) from these samples did not show any redistribution of As. The carrier concentration profiles from the spreading resistance measurements indicate that only 30% of As was electrically active. Comparison of XTEM and SIMS suggests that nucleation of the clusters occurred in the regions where As was present above the solid solubility limit in Si. The presence of recoiled oxygen has been found to stabilize the clusters.
Holographic moire deflectometry—A method for stiff density fields analysis
Authors: Stricker J. , Politch J.
Published: February 2003

This letter presents a method for the analysis of stiff density fields in which weak density gradients as well as strong ones, pointing in different directions, exist. Holographic techniques are used to freeze the deviated rays of a collimated beam traveling through a phase object. The hologram is post analyzed by the ‘‘moire deflectometry’’ method, where the sensitivity, the spatial resolution, and the direction along which the density gradients are measured, may easily be changed and adjusted to the different density regions in the field. It was found that this technique is very useful for short duration stiff fields where density mapping during one pulse is desired.
10-W cw optically pumped 12-μm NH3 laser
Authors: Rolland C. , Reid J. , Garside B. K.
Published: February 2003

A 37-W cw CO2 laser operating on the R(30) 9-μm transition is used to pump a linear waveguide cavity containing NH3. Raman emission at 12.08 μm is observed with a cw output power of 10.2 W. This performance represents a photon conversion efficiency of >40%, the highest yet reported for a cw optically pumped infrared laser.
Multicolor passive (self-pumped) phase conjugation
Authors: Cronin-Golomb Mark , Kwong Sze-Keung , Yariv Amnon
Published: February 2003

Passive phase conjugation of up to six lines (457, 476, 488, 496, 501, and 514 nm) of the all lines output of an argon ion laser is reported. Imaging characteristics and reflectivity measurements are given. In general, multiline operation results in some loss in both reflectivity and image resolution. This work opens the possibility for passive phase conjugation of full color images.
Changes in the optical reflectivity of implanted silicon as a function of implantation energy
Authors: Aharoni H. , Swart P. L.
Published: February 2003

Experimental results are presented regarding the changes in optical reflectivity of 31p+-implanted Si as a function of implantation energy. Three curves of R vs E are obtained for low, intermediate, and high doses. Each of them exhibits distinctly different reflectivity functions. However, they all indicate that the optical behavior at λ=632.8 nm is dominated by optical interference in the damaged layer and the crystalline silicon.
Liquid phase epitaxial growth of AlGaInPAs lattice matched to GaAs
Authors: Mukai S. , Yajima H. , Mitsuhashi Y. , Yanagisawa S. , Kutsuwada N.
Published: February 2003

Liquid phase epitaxial growth of (AlxGa1−x)1−zInzPyAs1−y lattice matched to GaAs is investigated. Uniform layers with high emission efficiency are obtained for x∼0.3 and y<0.1. Distribution coefficients of Al, Ga, In, P, and As at 850 °C are 100, 0.7, 0.03, 100, and 10, respectively. Interpolation formulae of composition dependence of energy gaps and of lattice constant are given and are compared with experimental results.
Identification of AsGa antisite defects in liquid encapsulated Czochralski GaAs
Authors: Elliott K. , Chen R. T. , Greenbaum S. G. , Wagner R. J.
Published: February 2003

We have identified the electron paramagnetic resonance (EPR) spectrum of the As on a Ga site (AsGa) defect in bulk undoped liquid encapsulated Czochralski grown GaAs. The intensity of the EPR signal can be correlated with the concentration of compensating carbon acceptors in the GaAs crystals. These results indicate that AsGa are responsible for the compensation of the undoped semi-insulating material, and thus can be identified with the deep donor EL2 in such material.
Correlation of acoustic emission with normal zone occurrence in epoxy-impregnated windings: An application of acoustic emission diagnostic technique to pulse superconducting magnets
Authors: Tsukamoto O. , Iwasa Y.
Published: February 2003

We report results of experiments correlating acoustic emission (AE) data to the presence of normal zones in epoxy-impregnated windings. The results suggest the feasibility of using AE sensors to determine whether or not a superconducting magnet has been driven normal after a rapid discharge. This AE diagnostic technique may be particularly valuable in application to pulse magnets.
Thermal effects of moderate substitutions of cobalt for iron in Fe76Pr16B8
Authors: Overfelt R. A. , Becker J. J.
Published: February 2003

We have explored the thermal effects of moderate substitutions of cobalt for iron in rapidly solidified, microcrystalline alloys of composition (Fe100−xCox)76Pr16B8, where x=0, 5, 10, 20, and 30. The maximum intrinsic coercivities were about 20 kOe and the saturation magnetizations were about 88 emu/g, both independent of cobalt content. A significant improvement in the Curie temperature of the hard phase is obtained with increasing cobalt content. A similar improvement in the reversible and irreversible temperature behavior is also observed as the cobalt content is increased.
Optical rotatory power of 90° twisted nematic liquid crystals
Authors: Wu Shin-Tson , Efron Uzi , Hess LaVerne D.
Published: February 2003

A technique was developed and used to measure the rotatory power of 90° twisted nematic liquid crystals in the visible and infrared spectral regions. Experimental results for two liquid crystal mixtures, BDH-E7 and ZLI-1132, are in very good agreement with theoretical calculations for a wide spectral range and for different liquid crystal thicknesses. A quantitative relationship between liquid crystal birefringence, wavelength, and cell thickness was derived for use in the design of IR liquid crystal light valves with high contrast ratios and minimum response times.
Surface deflection due to the presence of a crack in a half-space
Authors: Steele Charles R. , Yoo Seung-Hyun
Published: February 2003

An approximate solution is obtained for the normal displacement on the free surface of a half-space containing a crack perpendicular to the free surface. The crack has a finite width and the material is subject to a constant tensile stress. The procedure consists of first approximating the cracked layer as a beam on a rigid half-space. This provides a significant surface deflection. The deflection of the half-space due to the interface stresses is then added. Comparison with the exact solution for a crack of infinitesimal width and with experiments on finite width slots indicates that the approximate procedure is valuable for analyzing this and more complex configurations.