bluuebunny/crossref_metadata_2025 huggingface dataset:
Activation mechanism for Si implanted into semi-insulating GaAs
Authors: Hyuga Fumiaki , Watanabe Kazuo , Osaka Jiro , Hoshikawa Keigo
Published: July 2002

Hall effect and photoluminescence are measured for Si-implanted and SiO2-capped annealed GaAs, and for S-implanted and SiN-capped annealed GaAs. These experimental data are compared with those for Si-implanted and SiN-capped annealed GaAs. No remarkable change in sheet carrier concentration (Ns) is observed around dislocations and the SiAs photoluminescence peak is absent in the SiO2-capped annealed layer. Dislocations decrease Ns in the S-implanted layer. These results indicate that the activation efficiency of Si implanted into GaAs is determined by SiAs acceptor concentration.
Concentration ratio dependence of selective optical compensation effect in dually Zn+ and Se+ ion-implanted GaAs
Authors: Nomura Toshio , Makita Yunosuke , Irie Katsuhiro , Ohnishi Nobukazu , Kudo Kazuhiro , Tanaka Hideki , Mitsuhashi Yoshinobu
Published: July 2002

The selective optical compensation effect in which exclusively acceptor-associated emissions g and [g-g] are selectively quenched by the simultaneous presence of acceptor and donor atoms, was investigated in dually Zn+ (acceptor)-implanted and Se+(donor)-implanted GaAs as a function of Se to Zn concentration ratio, [Se]/[Zn], at a fixed Zn concentration of 1×1017 cm−3. It was revealed for the first time that Se atoms with one-tenth of the concentration of Zn have the ability to significantly suppress the [g-g] emission. However, the g emission is not significantly suppressed by the presence of even an equal concentration of Se atoms.
Metal deposition by electron beam exposure of an organometallic film
Authors: Craighead H. G. , Schiavone L. M.
Published: July 2002

We describe a method of metal deposition by electron beam exposure and pyrolysis of a gold containing organometallic polymer. Commercial gold containing solutions were used as negative electron beam resists with line dose sensitivities of about 0.2 μC/cm as developed in methylene chloride. We have demonstrated the formation of metal patterns on Si, GaAs, and polyimide with linewidths as small as 0.25 μm.
Morphological degradation of TiSi2 on 〈100〉 silicon
Authors: Revesz P. , Zheng L. R. , Hung L. S. , Mayer J. W.
Published: July 2002

Evidence of instability of TiSi2 layers during high-temperature high vacuum annealing has been observed. Rutherford backscattering and scanning electron microscopy measurements showed that at high vacuum annealing conditions, the laterally homogeneous silicide layer breaks up into islands. In between these TiSi2 islands, growth of an epitaxial silicon layer was observed.
Derivative photocurrent spectrum of an InGaAs/GaAs strained-layer superlattice
Authors: Fritz I. J. , Doyle B. L. , Drummond T. J. , Biefeld R. M. , Osbourn G. C.
Published: July 2002

We report the use of wavelength-modulated photocurrent spectroscopy to obtain detailed information on quantum well transitions in an In0.14Ga0.86As/GaAs strained-layer superlattice. The spectra are interpreted in terms of a Kronig–Penney model with literature values for offsets and deformation potentials. The effect of the test structure’s built-in electric field must be included to obtain agreement with this theory.
Improved performance of the discharge pumped HgBr and HgCl lasers by adding SF6
Authors: Sugii M. , Sasaki K.
Published: July 2002

The effects of adding electronegative SF6 to discharge pumped HgBr and HgCl lasers were compared with those without SF6. A 50% and 40% improvement of the output energies for HgBr and HgCl lasers was realized by adding SF6 to the optimized gas mixture.
Titanium-doped semi-insulating InP grown by the liquid encapsulated Czochralski method
Authors: Iseler G. W. , Ahern Brian S.
Published: July 2002

Semi-insulating crystals of InP with resistivities of 1–3×106 Ω cm have been grown by the liquid encapsulated Czochralski method from melts co-doped with Ti, a deep donor located 0.62±0.02 eV below the conduction band, and either Zn, Cd, or Be. This technique should make it possible to obtain crystals with resistivities of 107–108 Ω cm, which would be of interest for integrated circuit applications if their thermal stability were found to exceed that of Fe-doped semi-insulating InP.
Electrical and optical nonuniformity of Si-implanted and rapid thermal annealed InP:Fe
Authors: Rao Mulpuri V.
Published: July 2002

The radial variation in electrical and optical characteristics of Si-implanted InP:Fe wafer activated by rapid thermal annealing has been studied. The sheet carrier concentration (Ns) followed similar radial variation as etch pit density (EPD) whereas the photoluminescence (PL) intensity of C-Zn acceptor peak varied inversely with EPD. A maximum electron mobility of 2500 cm2/V s and electrical activation of 35% have been obtained for 3×1012 cm−2, 200 keV Si+ implants annealed for 15 s in the range 700–850 °C. A high intensity peak centered at 1.350 eV was also observed in the PL spectra of the samples and tentatively assigned to a Si-defect complex.
Effects of boron profiles on the open circuit voltage of p-i-n and n-i-p amorphous silicon solar cells
Authors: Jeffrey F. R. , Vernstrom G. D.
Published: July 2002

Data are presented showing that boron carryover into the i layer is responsible for the commonly observed difference in open circuit voltage between p-i-n and n-i-p amorphous silicon solar cells. It is proposed that the lower voltage samples are being limited by surface recombination at the p/i interface and that boron carryover reduces this recombination current. The Voc is then able to rise to the point where it is limited by the bulk recombination current.
Annealing of Si damage caused by reactive ion etching in SF6 gas mixtures
Authors: Pinto R. , Babu R. Sachidananda , Bhattacharya P. K.
Published: July 2002

Damage introduced in silicon during reactive ion etching (RIE) in SF6 gas mixtures has been studied using x-ray photoelectron spectroscopy, Schottky barrier measurements, and Rutherford backscattering. RIE was done at 0.1 W cm−2 power density with the rf cathode covered with a quartz plate, and the annealing behavior of damage was studied at various temperatures up to 800 °C in N2 ambient. The results obtained indicate the following: (a) contamination by F, S, and metal ions is insignificant; (b) lighter atoms such as hydrogen cause higher electrical damage and lower lattice damage, both of which can be annealed at 400 °C; (c) heavier atoms such as argon cause lower electrical damage but higher lattice damage which requires a temperature ≥800 °C for recovery.
Two-wavelength absorption modulation spectroscopy of bandtail absorption in GaAs quantum wells
Authors: Von Lehmen A. , Zucker J. E. , Heritage J. P. , Chemla D. S. , Gossard A. C.
Published: July 2002

We have discovered that below-band-gap photoexcitation produces large bleaching of the exciton absorption in GaAs quantum well heterostructures. We have used this effect to perform the first investigation of room-temperature bandtail absorption in these structures. We find that the below-band-gap absorption follows a spectral Urbach’s rule. In addition, proton-bombarded samples show an Urbach energy correlated with bombardment-induced defects. This sensitive technique has enabled us to study samples as thin as 1 μm at energies where the absorption coefficient is ∼10 cm−1.
High contrast, 1.3 μm optical AND gate with gain
Authors: Sharfin W. F. , Dagenais M.
Published: July 2002

A high contrast (5:1), 1.3 μm wavelength optical and gate is demonstrated using a bistable Fabry–Perot InGaAsP/InP laser amplifier with large gain. Using simple arguments, it is shown that, subject to realistic constraints, the maximum attainable contrast ratio in a bistable Fabry–Perot logic gate is about 10. Unlike bistable amplifiers, there is a significant trade-off between contrast and gain in passive devices.
Experimental realization of an n-channel double heterostructure optoelectronic switch
Authors: Taylor G. W. , Mand R. S. , Cho A. Y. , Simmons J. G.
Published: July 2002

An n-channel double heterostructure optoelectronic switch has been demonstrated. As in the case of the p-channel device, there is a high impedance state without light emission and a low impedance state with strong spontaneous emission. The states are changed by optical or electrical signals and a digital optical gain of 14 is observed. The switching voltage is higher and the holding current is lower than in the p-channel case.
Reduction of iron solubility in silicon with oxygen precipitates
Authors: Colas Etienne G. , Weber Eicke R.
Published: July 2002

The solubilities of iron in samples treated with various oxygen precipitation treatments were compared. The solubility of iron was reduced by almost two orders of magnitude in samples containing low-temperature oxygen precipitates. It is suggested that a new phase forms, probably an oxygen-metal rich compound that is more stable than the FeSi2 silicide. This study suggests dramatic improvements for the efficiency of gettering processes.
Double-injection field-effect transistor: A new type of solid-state device
Authors: Hack M. , Shur M. , Czubatyj W.
Published: July 2002

We propose a new general principle of operation for solid-state devices, and demonstrate a novel transistor which we call a double-injection field-effect transistor, based on this principle. We have fabricated amorphous silicon alloy double-injection transistors operating on the modulation of a double-injection current by a gate field covering the complete path of the current channel. Using these amorphous silicon alloy double-injection transistors, we have achieved currents over 20 times those theoretically possible for conventional amorphous silicon field-effect transistors operating under similar conditions. This new principle, applicable to both thin-film amorphous and crystalline devices, offers the potential of high-current, high-speed field-effect transistors with modulated optical emission.
InGaAs/InP p-i-n photodiodes grown by chemical beam epitaxy
Authors: Tsang W. T. , Campbell J. C.
Published: July 2002

Two types of mesa-type InGaAs/InP p-i-n photodiodes have been fabricated from wafers grown by chemical beam epitaxy (CBE): (1) a conventional diffused InGaAs homojunction and (2) a novel InP/InGaAs/InP double heterojunction. Both types of devices have exhibited very low dark current, good quantum efficiency of 70% (without antireflection coatings), and transit-time-limited pulse response. The lowest dark currents, less than 1 nA at −10 V bias, have been achieved with the double heterojunction devices in spite of the fact that the p-n junction is coincident with a heterojunction interface. This attests to the excellent quality of heterojunction interfaces grown by CBE. These results also unequivocally established that CBE is capable of producing high quality multilayer heterostructures for state-of-the-art device applications.
Phase locked narrow zinc diffused stripe laser arrays
Authors: Zmudzinski C. A. , Mawst L. J. , Givens M. E. , Emanuel M. A. , Coleman J. J.
Published: July 2002

Phase locked operation of an array of narrow diffused stripe conventional double heterostructure laser elements grown by metalorganic chemical vapor deposition is reported. Six-element arrays (length 356 μm) show threshold currents of 33 mA per stripe and peak power outputs of at least 160 mW per facet with total external differential quantum efficiencies of 33%. Complex near-field patterns are shown which result from two opposing mechanisms involved in guiding of the lateral modes. Three major lobes in far-field patterns, which correspond to expected patterns for the lateral modes of gain guided arrays, are described.
Doped hydrogenated amorphous silicon films by laser-induced chemical vapor deposition
Authors: Branz H. M. , Fan S. , Flint J. H. , Fiske B. T. , Adler D. , Haggerty J. S.
Published: July 2002

We report the growth and characterization of both n-type and p-type doped hydrogenated amorphous silicon films prepared by laser-induced chemical vapor deposition. For both doping types, the activation energy for electrical conduction has been reduced to below 0.2 eV and controlled doping has been achieved. Phosphine lowers the growth rate, while diborane has essentially no effect on the laser-induced growth but enhances thermal growth. Diborane also decreases the hydrogen concentration of the films, resulting in reduced optical gaps.
Inter-intramode correlation spectroscopy: A new experimental technique to study mode interaction in semiconductor lasers
Authors: Elsässer W.
Published: July 2002

A new experimental method to study modal interaction in semiconductor lasers is presented. The inter-intramode correlation spectroscopy investigates correlations between intensity and phase fluctuations having their origin in different longitudinal modes. First results for GaAs/(GaAl)As multimode lasers reveal correlated frequency fluctuations of the total longitudinal mode comb. Refractive index fluctuations and intermode coupling are discussed as the origin for these intramodal fluctuations.
Cerenkov maser operation at 1–2 mm wavelengths
Authors: Garate E. P. , Moustaizis S. , Buzzi J. M. , Rouille C. , Lamain H. , Walsh J. , Johnson B.
Published: July 2002

The interaction of a dense (n∼1012 cm−3), mildly relativistic (1.8<γ<3) electron beam and a cylindrical, dielectric lined waveguide has produced tunable microwave radiation in the 150–310 GHz frequency range with an estimated power output of 500 kW at 150 GHz and 10 kW at 310 GHz. The measured output frequency agrees well with the frequency for which the phase velocity of the TM01 mode of the dielectric lined guide is synchronous with the electron beam velocity.
Shallow p-type layers in InP by Hg implantation
Authors: Favennec P. N. , L’Haridon H. , Roquais J. M. , Salvi M. , Le Cleach X. , Gouskov L.
Published: July 2002

Ion implantation of mercury in n-type and semi-insulating indium phosphide is reported in InP. We show how mercury behaves in InP in terms of type of dopant, electrical activity, and diffusivity. Implanted mercury impurity behaves as an acceptor dopant in InP. Thin p-type layers have been obtained. Mercury profiles and electrical profiles show that mercury does not diffuse towards the bulk during annealing; therefore, mercury implantation can be a valuable technique in realizing shallow p-type layers in indium phosphide.
Charge-density fluctuations and spatial modulation of heavy- and light-hole-like character in GaAs-AlGaAs(001) superlattices
Authors: Gell M. A. , Jaros M.
Published: July 2002

We have used local pseudopotentials with spin-orbit coupling to illustrate some of the effects occurring in GaAs-AlGaAs (001) superlattices as a result of fluctuations in the widths of the layers. Full account is taken of the microscopic superlattice potential, and states associated with the principal as well as secondary band minima are presented. It is shown that fluctuations of only one monolayer can lead to a complete transfer of probability density into the lowest Γ-related symmetry-induced state. This also applies to states associated with the secondary band minima confined in the hot-electron range of energies. We also show that small fluctuations in layer width can be used to achieve a tunable spatial modulation of heavy- and light-hole-like character within the same superlattice state. We discuss some of the implications of our results for band structure engineering.
Mechanism for the threshold voltage shift of a GaAs field-effect transistor around dislocations
Authors: Miyazawa Shintaro , Wada Kazumi
Published: July 2002

The effect of gate-to-pit distance on threshold votlage for GaAs field-effect transistors was examined in detail for the area around dislocated ‘‘lineage’’ boundaries. From this investigation, a clear dislocation proximity effect is recognized. The most possible mechanism for threshold voltage shift is presented referring to the EL2 concentration increase at lineage and the model for EL2 formation previously reported. This model proposes the increase in As-interstitial concentration around dislocations, leaving a region of increased [VGa]/[VAs] ratio, is responsible for the threshold voltage shift.
New phase change material for optical recording with short erase time
Authors: Barton Roger , Davis Charles R. , Rubin Kurt , Lim Grace
Published: July 2002

We present data on a new erasable phase change medium, demonstrating for the first time that very short erase times can be obtained without sacrificing room-temperature stability of the amorphous state. Thin films of the composition Sb2Se underwent 10% relative reflectivity changes when switched with a laser between amorphous and crystalline states. Twenty milliwatt, 50 ns laser pulses were used for writing amorphous spots; 6.9 mW, 200 ns pulses were used for erasing. A playback carrier to noise ratio of 43 dB was observed on a plastic disk. Amorphous spots could be heated in a microscope to 175 °C before they crystallized. Transmission electron microscopy and x-ray diffraction indicate that the erased state is single phase and polycrystalline. The crystal structure, however, does not correspond to known compounds in the antimony-selenium system.
Influence of built-in strain on Hall effect in InGaAs/GaAs quantum well structures with p-type modulation doping
Authors: Fritz I. J. , Doyle B. L. , Schirber J. E. , Jones E. D. , Dawson L. R. , Drummond T. J.
Published: July 2002

Hall-effect data between 4 and 300 K on p-type strained quantum well structures in the InGaAs alloy system show pronounced effects due to the strain-induced splitting of the heavy- and light-hole valence bands. As a function of biaxial compression in the range 0.5–1.4%, the 77 K mobilities increase monotonically by a factor of ∼5, as does a high-temperature activation energy which is found to be nearly equal to the predicted strain splitting.
Well size dependence of Stark shifts for heavy-hole and light-hole levels in GaAs/AlGaAs quantum wells
Authors: Hiroshima T. , Lang R.
Published: July 2002

Stark shifts for heavy-hole and light-hole levels in an isolated GaAs/AlGaAs quantum well have been analyzed by an exact numerical calculation within the envelope function approximation. The calculated results predict that for wells thicker than about 100 Å the Stark shift for heavy hole is larger than that for light hole; however, for thinner wells this tendency is reversed. It also predicts that this well size dependence strongly depends on the band offset ratio.
Activated reactive evaporation of hydrogenated amorphous silicon nitride
Authors: Shufflebotham P. K. , White J. F. , Card H. C. , Kao K. C.
Published: July 2002

Activated reactive evaporation (ARE) of Si in NH3 and N2+H2 ambients has been used to fabricate amorphous Si:N:H thin films. The electrical and optical properties of these films are compared to those of evaporated a-Si and reactively evaporated a-Si:N:H. It is shown that the N2 and H2 gas mixture did not produce detectable N or H incorporation into the films, while substantial amounts of N and H were incorporated with NH3 gas. It is further shown that activated reactive evaporation with NH3 produces significantly more N and H incorporation than does reactive evaporation. This was clearly revealed in the electrical and optical properties of the films. The electrical and optical properties of the ARE films were comparable to materials produced by glow discharge techniques.
Optoelectrochemical impedance measurements: A new technique for the electrical characterization of dielectric/semiconductor interfaces
Authors: Stricot Y. , Clechet P. , Martin J. R.
Published: July 2002

We have developed a new method for the characterization of dielectric/semiconductor interfaces. This technique uses an electrolyte/dielectric/semiconductor structure under electrochemical potentiostatic polarization, and a weak modulated illumination with above-band-gap light which acts as a probe and does not modify the thermodynamic equilibrium of the electrochemical system too much. The analyzed photopotential relative to illumination in terms of impedance allows the characterization of the dielectric/semiconductor interface. To demonstrate the optoelectrochemical impedance measurement technique, results obtained on a p-Si/SiO2 sample are presented. The advantages of this method compared to purely solid-state impedance and electrochemical impedance measurements are discussed.
Magneto-optical properties of vacuum-deposited PtMnSb thin films
Authors: Inukai Takashi , Matsuoka Morito , Ono Kenichi
Published: July 2002

Magneto-optical properties for PtMnSb thin films, prepared by sequential vacuum deposition and annealing, are examined. PtMnSb thin films annealed at 500 °C exhibit a large Faraday rotation (θF) of 7.3×105 deg cm−1 as well as a large polar Kerr rotation (θK) of −1.8° at 633 nm. They transmit light well in the 400–900 nm wavelength range with an absorption coefficient (α) of 3.2×105 cm−1 at 633 nm. The magneto-optical figures of merit at 633 nm were 2θF/α =4.6 deg for transmitted light and (R)1/2θK =0.99 deg for reflected light.
Photocurrent amplification in Schottky photodiodes
Authors: Donald D. K. , Wang S. Y. , Ranganath T. R. , Newton S. A. , Trutna W. R.
Published: July 2002

Up to 20 dB of photocurrent amplification with a frequency response of 2 GHz has been observed in GaAs Schottky photodiodes. The amplification may be caused by a reduction in Schottky built-in potential under illumination. The device may find application in improving the sensitivity of optical receivers.
Evidence for electron-induced x-ray emission in sputtering deposition
Authors: Hecq M.
Published: July 2002

A new technique is shown to study in situ the chemical composition of sputtered films. The method is based on the x-ray emission induced by the fast electrons of the sputtering discharge. The sputtering chamber is coupled with a vacuum x-ray spectrometer. As a demonstration of the method, the Co deposition is studied. The Co Lα x-ray line and the deposition rate (by means of a quartz microbalance) are recorded as a function of time. X-ray intensity increases quickly during the first minutes of the deposition, then levels off gradually while the deposition rate remains constant. It is speculated that a fraction of a monolayer should be detectable.
p-channel, strained quantum well, field-effect transistor
Authors: Drummond T. J. , Zipperian T. E. , Fritz I. J. , Schirber J. E. , Plut T. A.
Published: July 2002

A p-channel field-effect transistor with a 3.5 μm Cr/Au gate was fabricated from a modulation-doped GaAs/In0.2Ga0.8As/GaAs quantum well structure. Well-behaved transistor action was observed at both 300 and 77 K with extrinsic transconductances of 6.2 and 11.3 mS/mm, respectively. Shubnikov–deHaas measurements prove the existence of a two-dimensional hole gas with a strain-shifted light-hole ground state associated with a light-hole mass of 0.154m0.
Electrical and thermal properties of new pyrographite films based on a condensation polymer, polyoxadiazole
Authors: Yasujima Hiroyuki , Murakami Mutsuaki , Yoshimura Susumu
Published: July 2002

Magnetoresistance, Hall coefficient, and thermal diffusivity of new high-quality graphite films prepared by pyrolysis of a condensation polymer, poly( p-phenylene-1,3,4-oxadiazole) were measured. The total carrier density, mobility, and thermal conductivity were 1.6×1019 cm−3, 7400 cm2 V−1 s−1, and 11 W cm−1 K−1 for the graphite film annealed at 3000 °C, which are almost comparable to those of highest quality graphites known so far. Drastic changes in the electronic and thermal properties with the heat-treatment temperature were found and discussed in relation to the development of the high-quality graphite.
Gaussian beam excitation of TE0 nonlinear guided waves
Authors: Wright E. M. , Stegeman G. I. , Seaton C. T. , Moloney J. V.
Published: July 2002

Selective, efficient excitation of TE0 nonlinear guided waves is demonstrated numerically. For a thin film bounded by two self-focusing media, three different field distributions corresponding to the same flux level can be excited independently by suitable Gaussian input beams.
Detection of In-P and In-Sb atom pairs by perturbed angular correlation in silicon
Authors: Swanson M. L. , Wichert Th. , Quenneville A. F.
Published: July 2002

We report the observation of In-P and In-Sb atom pairs in Si using the perturbed γγ angular correlation technique with 111In as radioactive probe atoms. The pairs are characterized by νQ=179(1) MHz and 271(1) MHz, respectively, and their electric field gradient tensors are axially symmetric about a 〈111〉 lattice direction. The results suggest a strong interaction between acceptor and donor atoms in elemental semiconductors like Si and Ge.
Formation of a superconducting hexagonal Nb-Si phase by pulsed laser quenching
Authors: Wang Wen-Kui , Spaepen Frans
Published: July 2002

A new metastable phase of composition NbxSi1−x (0.72<x<0.78) has been synthesized by nanosecond and picosecond pulsed laser quenching. The structure was studied by electron diffraction and found to be hexagonal with lattice parameters a=0.748 nm and c=0.514 nm (for x=0.75). The superconducting transition temperature Tc (for x=0.78) was 2.7 K.
Study of the low-temperature line broadening mechanisms for excitonic transitions in GaAs/AlGaAs modulator structures
Authors: Hong S. , Singh Jasprit
Published: July 2002

We examine the dominant line broadening mechanisms for excitonic lines in a quantum well in the presence of strong transverse electric fields. We have calculated the line broadening due to interface roughness effects and lifetime broadening effects. We find that the line broadening effects due to interface roughness increase rapidly as the transverse electric field is increased and for a 100-Å Al0.3Ga0.7As/GaAs well, increase by a factor of ∼2.0 as the field is increased from 0 to 100 kV/cm. The broadening due to lifetime effects is very sensitive to the band lineup assumed and is much smaller than interface roughness effects even for one monolayer interface roughness.
Calibration of the carbon localized vibrational mode absorption line in GaAs
Authors: Brozel M. R. , Foulkes E. J. , Series R. W. , Hurle D. T. J.
Published: July 2002

The residual carbon acceptor concentration [CAs] in three radio-tin-doped, liquid encapsulated Czochralski, GaAs single crystals was estimated from a plot of carrier concentration versus tin concentration determined by radio-tracer counting. Local vibrational mode absorption of CAs in the samples was measured at room temperature and a calibration factor of 8±2×1015 cm−1 obtained. A comparison of this with other determinations suggests that the true calibration factor lies between 8 and 11×1015 cm−1 and that earlier, larger calibration factors should be discounted.
Electron mobility and velocity in compensated GaAs
Authors: Xu Jingming , Bernhardt Bruce A. , Shur Michael , Chen Chung-Hsu , Peczalski Andrzej
Published: July 2002

We present the results of a Monte Carlo calculation of the electron velocity and mobility, as well as mobility measurements in compensated GaAs. For appreciable compensation ratios, the peak velocity, negative differential mobility, and peak-to-valley velocity ratios are drastically reduced in comparison with those in uncompensated GaAs. This reduction makes the Gunn effect less likely to manifest itself in ion-implanted GaAs metal-semiconductor field-effect transistors and other GaAs devices where compensation is important.
Improvements in AlGaAs laser diodes grown by molecular beam epitaxy using a compositionally graded buffer layer
Authors: Hayakawa T. , Suyama T. , Kondo M. , Takahashi K. , Yamamoto S. , Hijikata T.
Published: July 2002

The effect of a compositionally graded buffer layer (CGBL) in AlGaAs laser diodes grown by molecular beam epitaxy is presented. The threshold current and the differential quantum efficiency are improved by a factor of ∼2. The lifetime is markedly improved by using a CGBL and it is comparable to that of lasers grown by liquid phase epitaxy.
Electron beam stimulated chemical vapor deposition of patterned tungsten films on Si(100)
Authors: Jackman R. B. , Foord J. S.
Published: July 2002

Electron irradiation of WF6 films on Si has been studied using scanning Auger and electron microscopic techniques. In contrast to metal organics, electron stimulated decomposition of WF6 is found to result in formation of pure W deposits; patterned films are formed by scanning the focused electron beam. The morphology of the films is particulate and the manner in which this originates is discussed.
Quenched-in defects in flashlamp-annealed silicon
Authors: Borenstein J. T. , Jones J. T. , Corbett J. W. , Oehrlein G. S. , Kleinhenz R. L.
Published: July 2002

Deep levels introduced in boron-doped silicon by heat-pulse annealing with a tungsten-halogen flashlamp are investigated using deep level transient spectroscopy. Two majority-carrier trapping levels in the band gap, at Ev+0.32 eV and at Ev+0.45 eV, are observed. These results are compared to those obtained by furnace quenching and laser annealing studies. Both the position in the gap and the annealing kinetics of the hole trap at Ev+0.45 eV suggest that this center is due to an interstitial iron impurity in the lattice. The deep levels are not consistently observed in all flashlamp-annealed Si crystals utilized in the present work.
Minority-carrier mobility anomalies in low-resistivity silicon solar cells
Authors: Weizer V. G. , DeLombard R.
Published: July 2002

Measurement of the minority-carrier mobility in the base region of the high-voltage metal-insulator-N-P solar cell, as well as in other 0.1 Ω cm cells, provides direct proof that the high voltages measured for that cell are due not only to improved emitter characteristics but to an improved base region as well. The base characteristics are shown to be quite sensitive to the effects of diffusion induced lattice stress originating in the emitter. The implications of these findings with regard to the fabrication of high efficiency cells are discussed.
Highly efficient, long lived AlGaAs lasers fabricated by silicon impurity induced disordering
Authors: Thornton R. L. , Burnham R. D. , Paoli T. L. , Holonyak N. , Deppe D. G.
Published: July 2002

The process of silicon impurity induced disordering has been used to fabricate very efficient buried heterostructure AlGaAs lasers with lifetimes in the thousands of hours at 50 °C. These devices operate in a single transverse mode up to 25 mW, and in a single longitudinal mode with adjacent mode suppression of 23 dB.
Surface photovoltage measurement of light instability of amorphous silicon films
Authors: Epstein K. A. , Tran N. T. , Jeffrey F. R. , Moore A. R.
Published: July 2002

The effect of prolonged light exposure on photovoltaic quality of glow discharge amorphous silicon films has been studied by the surface photovoltage technique. Two principal results have been observed. (i) The minority-carrier diffusion length degrades but stabilizes at 0.25–0.3 μm. (ii) The space-charge width collapses at open circuit voltage under as little as 0.0001 sun bias illumination. The combination of these two effects suggests that it is gross changes in the built-in electric fields that most seriously degrade the fill factor in amorphous silicon solar cells, rather than changes in μτ.
Narrow linewidth, single frequency semiconductor laser with a phase conjugate external cavity mirror
Authors: Vahala Kerry , Kyuma Kazuo , Yariv Amnon , Kwong Sze-Keung , Cronin-Golomb Mark , Lau Kam Y.
Published: July 2002

We measure the spectral characteristics of an external cavity semiconductor laser which uses a phase conjugate mirror for its external reflection. This device has significant advantages over the conventional external cavity system owing to the self-aligning nature of the phase conjugate mirror. The fiber delay line self-heterodyne technique is used to measure the fundamental linewidth for single mode operation of this device. It shows the linewidth to be at least as narrow as the instrumental resolution of 100 kHz.
Low threshold 1.51 μm InGaAsP buried crescent injection lasers with semi-insulating current confinement layer
Authors: Cheng W. H. , Su C. B. , Buehring K. D. , Chien C. P. , Ure J. W. , Perrachione D. , Renner D. , Hess K. L. , Zehr S. W.
Published: July 2002

A hybrid growth technique has been used to fabricate low threshold 1.51 μm InGaAsP buried crescent injection lasers with a semi-insulating current confinement layer. The technique involves a first stage of low pressure metalorganic chemical vapor deposition followed by a liquid phase epitaxy stage. The lasers exhibit cw threshold currents as low as 12 mA at 25 °C, high yield, differential quantum efficiency over 41%, and output power more than 18 mW. Small-signal modulation response to 3.5 GHz has been obtained. The lasers show an initial small degradation rate of 1%/kh at 50 °C which gives an estimated operating lifetime of 47 years at 25 °C.
Analysis of a Y-junction semiconductor laser array
Authors: Streifer William , Cross Peter S. , Welch David F. , Scifres Don R.
Published: July 2002

An analysis of a new type of high power semiconductor laser array is presented. The array consists of parallel, uncoupled waveguides linked at Y junctions in one region. We show that for the lowest threshold array mode all the waveguides oscillate in phase and all (except possibly the outermost) have equal amplitudes. The array mode should be stable above threshold and it radiates in a single-lobe far-field pattern if the individual waveguide mode width is comparable to the guide separation.
Frequency limit of double barrier resonant tunneling oscillators
Authors: Coon D. D. , Liu H. C.
Published: July 2002

The frequency limit of negative differential resistance (NDR) devices employing resonant tunneling in double barrier quantum well structures is analyzed. We show that the standard theoretical approach to resonant tunneling together with a unitarity bound leads to a lower bound on NDR which is in turn related to the maximum oscillator frequency. The bound on NDR can be achieved in devices with narrow width resonances. However, too narrow a width can cause Wigner–Eisenbud resonance time delay. These considerations indicate that devices of the type studied by T. C. L. G. Sollner, P. E. Tannenwald, D. D. Peck, and W. D. Goodhue [Appl. Phys. Lett. 45, 1319 (1984)] could oscillate up to roughly 1 THz.
Threshold current of single quantum well lasers: The role of the confining layers
Authors: Nagle J. , Hersee S. , Krakowski M. , Weil T. , Weisbuch C.
Published: July 2002

The threshold current density of single quantum well (SQW) GaAs/GaAlAs lasers is calculated, taking into account the carrier populations of the confining layer. We find that these populations are significant when compared to those of the quantum well. This effect explains the better performance of the graded-index separate confinement SQW laser when compared to the separate confinement heterostructure laser, as well as the T0 performance of such lasers.
Effect of ion beam mixing on wear and friction of Fe-Ti multilayered structure on AISI 304 stainless steel
Authors: Hirvonen J-P. , Nastasi M. , Mayer J. W.
Published: July 2002

Dry sliding properties of ion beam mixed multilayered Fe-Ti structures deposited on AISI 304 stainless steel were studied over the composition range 0–100% Ti using samples with a linearly varying composition of constituents. Our measurements revealed that a ductile surface was formed with good sliding properties over the wide composition range by ion beam mixing of deposited layers. These beneficial effects were not obtained on as-deposited samples or by ion bombardment of either a substrate or pure iron layer deposited on a substrate. Thus, it is concluded that both the ion beam processing and composition as well as the resulting microstructure are essential for improved tribology.
Electron spin resonance study of high field stressing in metal-oxide-silicon device oxides
Authors: Warren W. L. , Lenahan P. M.
Published: July 2002

We find that two paramagnetic ‘‘trivalent silicon’’ centers appear to be responsible for damage resulting from Fowler–Nordheim injection of electrons into thermal oxides on silicon.
Fast shrinkage of oxidation stacking faults during O2/NF3 oxidation of silicon
Authors: Kim U. S. , Jaccodine R. J.
Published: July 2002

The behavior of oxidation-induced stacking faults (OSF’s) during the O2/NF3 oxidation of silicon has been investigated in the temperature range of 850–1100 °C. A very fast shrinkage rate of pregrown OSF in silicon and a nonlinear shrinkage rate with time have been observed. The shrinkage rate of OSF decreases as the oxidation time is increased. It is proposed that the fast OSF shrinkage is due to excessive vacancy flux as a result of the reaction of fluorine at the Si/SiO2 interface during the initial transient state, and subsequently the shrinkage rate is reduced as the steady-state condition of vacancy-interstitial recombination is approached. It has also been found that no OSF’s are generated even when mechanical damage by abrasion is done prior to oxidation.
New singlet oxygen generator for chemical oxygen-iodine lasers
Authors: Yoshida S. , Saito H. , Fujioka T. , Yamakoshi H. , Uchiyama T.
Published: July 2002

Experiments have been carried out to investigate a new method for generating O2(1Δ) with long-time operation of an efficient chemical oxygen-iodine laser system in mind. An impinging-jet nozzle was utilized to atomize a H2O2-KOH solution so that the alkaline H2O2/Cl2 reaction might occur in droplet-gas phase with high excitation efficiency. Experimental results indicate that the present generator can yield as high as 80% of O2(1Δ) with reasonable O2 flow rate.
Low threshold operation of a GaAlAs/GaAs distributed feedback laser with double channel planar buried heterostructure
Authors: Nakano Yoshiaki , Tada Kunio
Published: July 2002

We describe a GaAlAs/GaAs distributed feedback (DFB) laser with double channel planar buried heterostructure operating at λ=0.88 μm. The device has been prepared using three-step liquid phase epitaxy. A cw threshold current as low as 12 mA at room temperature has been accomplished even with third-order diffraction gratings. A single longitudinal mode oscillation without mode hopping has been observed at any injection level over a temperature range of 60 K. These characteristics are indeed almost comparable to the well-developed quaternary counterparts, thus showing that the excellent spectral purity of DFB lasers will soon be available in the fields where shorter wavelengths are needed.
Ion beam induced conductivity and structural changes in diamondlike carbon coatings
Authors: Prawer S. , Kalish R. , Adel M. , Richter V.
Published: July 2002

Energetic ion beam irradiation of diamondlike carbon thin films induces a decrease of 4–5 orders of magnitude in the resistivity of the films from their as-grown value of 107 Ω cm. The initial decrease in resistivity with increasing ion dose is due to the loss of hydrogen from the films with a concomitant decrease in the optical band gap. Heating the films during the irradiation greatly accelerates the rate of hydrogen loss as a function of dose. Once the hydrogen removal is complete, further irradiation increases the film conductivity by inducing the growth of microcrystallites of graphite.
Ni-C multilayer reflectivity and photoelectron yield in the NiL-edge region
Authors: van Brug H. , Bruijn M. P. , van der Pol R. , van der Wiel M. J.
Published: July 2002

We analyze measurements of the x-ray reflectivity and photoelectron yield of a Ni-C multilayer (103 layers; d=31 Å) in the NiL-edge region (700–950 eV). The measured reflectivity is shown to be consistent with the one calculated using x-ray scattering factors  f1 and  f2 for Ni as obtained from the photoelectron yield (∼f2). The analysis yields a new set of ‘‘effective’’ values for  f1 in the NiL-edge region.
Strain relief in epitaxial fluoride buffer layers for semiconductor heteroepitaxy
Authors: Zogg H.
Published: July 2002

Strain in epitaxial BaF2 layers grown by molecular beam epitaxy on CaF2 covered Si is found to be completely relieved at room temperature in films thicker than ∼250 nm, despite a large lattice and thermal expansion mismatch. In thinner films, planar tensile strain up to 5×10−3 is observed. Partial or complete strain relief occurs during temperature cycling near room temperature, and even if further layers are grown on top of the BaF2 film. This suggests that such films may be of use as buffers to relieve stresses in heteroepitaxial semiconductor-on-semiconductor structures.
Laser direct writing of single-crystal III-V compounds on GaAs
Authors: Karam N. H. , El-Masry N. A. , Bedair S. M.
Published: July 2002

Laser selective chemical vapor deposition and direct writing of GaAs and its ternary alloys with P have been achieved on GaAs substrates. An Ar+ laser is used to locally heat areas where selective deposition is desired on a substrate which is uniformly biased to a temperature in the range of 25–500 °C. Epitaxial growth was achieved by carefully controlling the deposition parameters to reach growth rates low enough, typically 20 Å/s, for the reaction kinetics of the pyrolitic process to take place. Cross-sectional transmission electron microscopy and photoluminescence results indicate that the quality of the deposited material is comparable to that grown with the conventional metalorganic chemical vapor deposition technique.
Internal thermal stress distribution in InGaAsP/InP lasers
Authors: Liu J. M. , Chen Y. C. , Wayne S. F.
Published: July 2002

The two-dimensional distribution of the internal thermal stress in the active layer of a buried heterostructure InGaAsP/InP laser is calculated with the finite-element method for active regions of both rectangular and crescent shapes. The shape and the finite width of the stripe cause nonuniform distribution of the thermal stress in the active layer. The results show different distributions for these two shapes, particularly near the edges of the active regions. Large stress and stress gradient are found around the tips of the crescent, which may imply problems such as defects and mode instability in real devices.
Parametric amplification sampling spectroscopy of luminescence at the subpicosecond time scale in the 1–1.6 μm spectral range
Authors: Hulin D. , Migus A. , Antonetti A. , Ledoux I. , Badan J. , Oudar J. L. , Zyss J.
Published: July 2002

A new method for time-resolved luminescence spectroscopy with subpicosecond resolution is proposed in the 1–1.6 μm spectral range, using parametric amplification in a highly nonlinear organic crystal. This technique is used to characterize the luminescence of an infrared dye and of an InGaAs-InAlAs multiple quantum well structure.
Timing jitter in mode-locked and gain-switched InGaAsP injection lasers
Authors: Taylor A. J. , Wiesenfeld J. M. , Eisenstein G. , Tucker R. S.
Published: July 2002

Pulse-to-pulse timing jitter in both mode-locked and gain-switched InGaAsP injection lasers is characterized. The measured jitter is less than 1 ps and is significantly less than the jitter reported for other laser systems. It is due almost entirely to the jitter in the frequency synthesizer and amplifier that electrically drive the injection laser.
Resonant injection quantum well lasers
Authors: Schulman J. N.
Published: July 2002

The efficient capture of injected electrons by quantum wells is important for minimizing the threshold currents of quantum well lasers. This is especially true for thin wells, where the electrons may not spend enough time in the wells to lose energy and fall into the confined lasing level. Since the band-gap enhancement is greatest for thin wells, it is highly desirable to design structures for which the electron density in the well region is as high as possible, thus maximizing the probability of scattering and decay into the lasing level. Here, we investigate theoretically several related structures for which the incoming electrons encounter a resonance in the quantum well region, producing an enhanced electron density there. This is achieved by adding a thin high alloy concentration barrier adjacent to the well, and by choosing the alloy concentrations outside the barrier to line up the incoming electrons with a higher resonance in the well. Calculations for the GaAs-GaAlAs case demonstrating the effect are shown. An order of magnitude increase in the electron density in the well, as compared to the simple quantum well, is achieved.
Optoelectronic and structural properties of sputter etched surfaces of InP
Authors: Olego D. J. , Schachter R. , Viscogliosi M. , Bunz L. A.
Published: July 2002

The effects of sputter etching on the optoelectronic and structural properties of 〈100〉 surfaces of InP were investigated by photoluminescence (PL) and Raman scattering in conjunction with capacitance-voltage determinations of the density of surface state Nss. The surfaces were etched in an Ar+ plasma for 5 min with plasma power densities D up to 0.1 W cm−2. The near band edge PL intensity shows a striking dependence on D. Below the threshold for macroscopic structural damage, the behavior of the PL and the Nss are independent of each other. A movement of the Fermi level at the surface is invoked in order to explain the PL response.
Tungsten deposition on porous silicon for formation of buried conductors in single crystal silicon
Authors: Tsao S. S. , Blewer R. S. , Tsao J. Y.
Published: July 2002

We report measurements of the kinetics of tungsten metallization of porous silicon layers for the formation of buried conductors under single crystal silicon. The kinetics depend markedly on the partial pressure of the source gas and on the degree of porosity, in agreement with a proposed model in which the rate-limiting step is diffusion of WF6 source gas through the narrow pore channels. Preliminary results are presented of the full isolation of silicon islands by buried metal.
Experimental relation between cut-off wavelength and HgTe layer thickness for HgTe-CdTe superlattices
Authors: Reno J. , Faurie J. P.
Published: July 2002

An experimental curve of room-temperature cut-off wavelength versus HgTe layer thickness for HgTe-CdTe superlattices is presented for the first time, along with an experimental equation relating the two. The equation is used to show that the variation in the cut-off wavelength for HgTe-CdTe superlattices is less than for HgCdTe alloy when the cut-off wavelength is greater than 2.0 μm.
Surface state density distribution at an Al2O3-InP metal-insulator-semiconductor field-effect transistor measured by the charge pumping technique
Authors: Kobayashi Takeshi , Ichikawa Tohru , Sawai Tetsurou
Published: July 2002

The surface state density distribution Nss at an InP-Al2O3 interface beneath the gate electrode was obtained by applying the charge pumping measurement technique to the n-channel inversion-mode Al2O3-InP metal-insulator-semiconductor field-effect transistors. The observed Nss versus energy curve was U shaped spreading over the energy between the conduction-band edge and 1 eV above the valence-band edge. The result was in good agreement with that obtained from the capacitance-voltage curves of the metal-insulator-semiconductor diode by the Terman method.
Response to ‘‘Comment on ‘Galvanomagnetic luminescence of indium antimonide’ ’’ [Appl. Phys. Lett. 4
9, 537 (1986)]
Authors: Berdahl Paul , Shaffer Louie
Published: July 2002

The authors respond to the comments of Morimoto and Chiba by pointing out that the authors theory and unpublished data on the galvanomagnetic luminescence in indium antimonide supports the conclusion that the emission intensity is independent of the thickness for values of the thickness (d) much larger than the effective diffusion length L (3 microns). This contradicts the conclusion of Morimoto and Chiba who determined that the emission varied as d−2.(AIP)