bluuebunny/crossref_metadata_2025 huggingface dataset:
Intensity self-pulsations in (GaAl)As injection lasers operating in an external cavity
Authors: Figueroa Luis , Lau Kam , Yariv Amnon
Published: February 2003

We present an experimental and theoretical study of a self-pulsing (GaAl)As injection laser operating in an external cavity. We have observed suppression of the self-pulsations when the external cavity is in the range 6<L<10 cm. Suppression of self-pulsations can also be obtained by using a multimode graded index optical fiber as the external resonator. These results can be explained by a model which includes the effects of an external cavity and electron trapping. For long cavity lengths, the self-pulsation frequency locks to an external cavity harmonic with no significant quenching, as observed in some earlier experiments.
Ionization coefficients measured in abrupt InP junctions
Authors: Umebu I. , Choudhury A. N. M. M. , Robson P. N.
Published: February 2003

The ionization coefficients of electrons α (Em ) and holes β (Em) in (100) InP have been obtained by photomultiplication measurements on abrupt Cd-doped LPE p+-n junctions having a donor concentration of 1.3×1017 cm−3. Two different methods of producing pure hole injection have been used which give identical results. In the electric field range 5×105<Em <8×105 V cm−1, β≳α and the coefficients may be expressed as α (Em) =7.36 ×106 exp(−3.45×106/Em) cm−1, β (Em ) =2.04×106 exp(−2.42×106/Em ) cm−1. The breakdown voltages calculated using these values of α and β show good agreement with experimental results.
Capture from free-carrier tails in the depletion region of junction barriers
Authors: Grimmeiss H. G. , Ledebo L.-Å. , Meijer E.
Published: February 2003

Junction experiments have been proposed in which measurements of depletion capacitance as a function of decreasing reverse bias are used to determine the energy level of a deep trap. Since deep levels in the depletion layer are filled from the free-carrier tail extending from the bulk, this process is slow to reach equilibrium. Calculation and experiment demonstrate this effect and it is emphasized that its neglect leads to serious misinterpretation.
A correlation between electron traps and growth processes in n-GaAs prepared by molecular beam epitaxy
Authors: Neave J. H. , Blood P. , Joyce B. A.
Published: February 2003

By using a single Knudsen source independently to generate molecular beams of As2 and As4 from elemental arsenic, a direct correlation has been observed between the arsenic species used and deep level concentrations in molecular beam epitaxy grown n-type GaAs films. Some preliminary observations on comparative growth temperature effects and Ge site occupancy are also reported.
High photocurrent polycrystalline thin-film CdS/CuInSe2 solar cella
Authors: Mickelsen R. A. , Chen Wen S.
Published: February 2003

A polycrystalline thin-film Cds/CuInSe2 heterojunction solar cell with an efficiency of 5.7% has been prepared using a simultaneous elemental evaporation technique to deposit the CuInSe2 film. The cell–s short(-circuit current of 31 mA/cm2 under 100 mW/cm2 is the highest ever reported for a 1-cm2 cell. Heat treatments have been found to improve cell efficiency and to also change the cell I-V and C-V characteristics.
The capacitance of degenerate-semiconductor Schottky barriers at low temperatures
Authors: Stoeckly Beth
Published: February 2003

The low-temperature capacitance of Schottky barriers formed by degenerate-semiconductor–metal junctions is of interest in building semiconductor membrane Josephson devices. The capacitance calculated within the depletion approximation is shown to be exact, and the barrier height calculated within the depletion approximation differs from the real barrier height be a small amount which can be calculated if the density of states is known.
Gain measurements on the triatomic excimer Xe2Cl
Authors: Tang K. Y. , Lorents D. C. , Huestis D. L.
Published: February 2003

Transient gain on the Xe2Cl* blue-green emission continuum has been observed at 488.0,. 497.6, and 514.5 nm. A maximum of 6% per pass was obtained using gas mixtures of Ar/Xe/CCl4 pumped by short, intense electron beam pulses. The stimulated emission cross section, ∼8×10−18 cm2, as derived from the fluorescence spectrum, is consistent with the observed gain. The gain characteristics of Xe2Cl* are similar to those observed in the XeF (C→A) system.
External cavity operated angled-stripe geometry DH lasers
Authors: Holbrook M. B. , Bradley D. J. , Kirkby P. A.
Published: February 2003

Complete elimination of feedback reflections from the cleaved facets of GaAs/GaAlAs double-heterostructure injection lasers has been achieved. This results in smooth amplified spontaneous emission spectra, from diodes modified by a combination of antireflection coating and angled stripe contacts, at currents greater than 2.5 times the cw threshold for unmodified lasers. The angled-stripe lasers operate in a two-mirror cavity producing smooth spectra with 1-Å (FWHM) bandwidths.
Half-ring (GaAl)As double-heterojunction injection lasers
Authors: Liao Andrew Shuh-Huei , Wang Shyh
Published: February 2003

We report room temperature operation of injection-pumped (GaAl)As half-ring lasers with high mesa stripe geometry. The performance of these lasers is compared with that of the corresponding straight laser. The outstanding features of the half-ring laser are: (1) Large variation of the far-field patterns both in shape and in main-lobe position with the length of the straight section, (2) improved L-I characteristics, and (3) cleaner longitudinal mode spectra. These observations suggest that the lateral modes in a composite cavity oscillate as a whole to form a hybrid mode. Such hybridization should lead to greater mode stability.
Observation of charge storage and charge transfer in a GaAlAsSb/GaSb charge-coupled device
Authors: Liu Y. Z. , Deyhimy I. , Harris J. S. , Anderson R. J. , Appelbaum Jacob , Pollard J. H.
Published: February 2003

A heterojunction charge-coupled device (CCD), where the CCD channel is formed in the wider-band-gap material confined between the p-n heterojunction and a Schottky barrier, has been demonstrated in the GaAlAsSb/GaSb system. Charge storage and charge transfer were observed at 77 °K. Analysis of the charge filling time revealed that the dark current was not dominated by thermal generation but possibly by a leakage current between the channel and its guard ring. Nevertheless, a charge filling time as long as 450 sec has been observed. With the heterojunction design, the band gap of the CCD channel can be chosen independently from the band gap of the optical absorber. Therefore the GaAlAsSb heterojunction CCD has potentially better performance in imaging between 1.0 and 1.8 μm than a conventional homojunction CCD.
Interface-state parameter determination by deep-level transient spectroscopy
Authors: Tredwell T. J. , Viswanathan C. R.
Published: February 2003

A modification of the deep-level transient spectroscopy (DLTS) technique for determination of interface-state parameters is described. In this technique, the surface potential dependence of the interface-state emission signal in a MOS capacitor was used to determine the energy of the emitting states. The technique allows accurate determination of majority-carrier cross section and interface-state density as functions of energy in the gap. Experimental results are presented for n- and p-type MOS capacitors on n 〈100〉 silicon.
Improvement of photoluminescence property of (GaAl)As double-heterostructure laser wafer with buffer layer
Authors: Shima K. , Takagi N. , Segi K. , Imai H. , Hori K. , Takusagawa M.
Published: February 2003

The effect of a buffer layer on a (GaAl)As double-heterostructure wafer is examined by a photoluminescence (PL) technique. It is found that a buffer layer improves the radiative efficiency and lasing characteristics. There exists a good correlation between the buffer-layer thickness, and the PL intensity of an active layer and the threshold current density.
406-nm laser on the C→B band of N2
Authors: Eden J. G.
Published: February 2003

Intense visible laser emission on the 0-3 transition of the N2 (C→B) band at 405.9 nm has been observed by exciting Ar/5–10% N2( pTOTAL ≈2000 Torr) gas mixtures with a long-pulse (∼0.5 μs) electron beam of cylindrical symmetry. The experimental apparatus consists of a coaxial diode of 50 cm length and 250 cm3 anode volume driven by a low inductance, ∼250-kV Marx generator. Lasing on the violet line occurs following bottlenecking of the 0-1 and 0-2 ultraviolet laser transitions. With ∼0.8% output coupling at 406 nm, a maximum output energy of 2.2 mJ in a 200-ns FWHM pulse has been obtained in the violet which is comparable to that extracted (for optimum mirror transmission) on the 358- and 380-nm UV laser lines.
Stimulation of far-infrared emission produced by impact ionization in Ge(Sb)
Authors: Williams W. D. , Fan H. Y.
Published: February 2003

Far-infrared radiation, in the wavelength range (∼70–170 μm), emitted by Ge(Sb) at LHE temperature was investigated. The recombination radiation was produced by impact ionization due to an applied electric field of the order of 10 V/cm. Measurements were made with the sample open and with the sample in some enclosure. The results show that the increased radiation intensity in the enclosed sample enhanced considerably the significance of induced emission.
Optical determination of smectic A layer spacing in freely suspended thin films
Authors: Rosenblatt Charles , Amer Nabil M.
Published: February 2003

Optical measurements of smectic A layer spacings in freely suspended thin films of three liquid crystals are reported. Although the measured spacings are close to those reported for the bulk, some anomalous behavior is noted. In addition, we report that the smectic A phase in the film can exist at unusually high temperatures.
The In-Ga-As-Zn system: LPE growth conditions for lattice matching on (111) B InP substrates
Authors: Benchimol J. L. , Quillec M. , Le Cornec C. , Le Roux G.
Published: February 2003

Experimental and calculated partial phase diagrams for the In-Ga-As-Zn system are presented. The distribution coefficient for gallium between the solid and liquid phase is found to increase significantly with increasing Zn concentration in the liquid. Growth conditions for Zn-doped In0.53Ga0.47As layers lattice matched to (111) B InP substrates are determined. Electrical characteristics of the layers are also reported.
Dark current and breakdown characteristics of dislocation-free InP photodiodes
Authors: Lee T. P. , Burrus C. A.
Published: February 2003

The reverse I-V characteristics of InP p-n junction mesa photodiodes carefully fabricated to contain only a small number of dislocation etch pits were studied and compared. The results show that I varies with V approximately as expected for defect-free junctions only when the mesas contain no visible etch pits.
p
n-diode array optical imager scanned with a single acoustic surface wave pulse
Authors: Stueflotten S.
Published: February 2003

A simple image scanning technique applied to the pn-diode/LiNbO3 airgap convolver structure is described. The image sensor is read out by means of a single acoustic surface wave pulse. Through a nonlinear mixing the output signal is retrieved at the second harmonic of the input frequency. It is essential to the principle of operation that the acoustic wavelength match the diode period. Fourier transform scans of optical images may also be performed by the same device.
Acoustic phenomena in erosion of spark-gap electrodes
Authors: Petr R. A. , Burkes T. R.
Published: February 2003

Experiments have been conducted to show that acoustic waves generated in the electrode material may cause an order-of-magnitude increase in the rate of electrode erosion. This increase is due to the arrival of reflected acoustic waves at the electrode surface while arc ’’spots’’ are still molten.
Laser annealing of Bi-implanted ZnTe
Authors: Bontemps A. , Campisano S. U. , Foti G. , Mondio G. , Saitta G.
Published: February 2003

Bismuth-implanted zinc telluride has been annealed by high-power ruby laser pulses. Owing to its band gap (2.28 eV) the crystalline ZnTe is transparent to the ruby radiation while the implanted material is absorbing, leading to selective annealing. Channeling and reflectivity measurements indicate a progressive reordering with increasing energy density.
Trace detection in gases using phase fluctuation optical heterodyne spectroscopy
Authors: Davis Christopher C.
Published: February 2003

A very sensitive technique for detecting trace molecules in the gas phase is described. Refractive index changes of a gaseous sample, which result following V→R, T relaxation of trace molecules which have been excited by a laser, are detected by optical heterodyning in a Mach-Zender interferometer. Detection sensitivities of 10 ppb for SF6 in air and 40 ppb for CH3OH in helium, have been demonstrated using CO2 TEA laser excitation and a 20-MHz detection bandwidth.
Multiscanning electron beam annealing of phosphorus-implanted silicon
Authors: Bentini G. G. , Galloni R. , Nipoti R.
Published: February 2003

(100) Si wafers implanted with 31P+ ions (100 keV, 2×1015 cm−2) have been annealed with a multiscanning electron beam by using a fusion electron gun. The main results obtained are (i) the multiscan electron beam annealing technique can be used to obtain excellent annealing of the damaged layer, (ii) the electrical activity and the mobility values of electron-annealed specimens are the same as for control samples annealed at 900 °C for 30 min., (iii) in contrast with furnace annealing, the multiscan electron beam annealing technique does not degrade the lifetime of the base material, and (iv) carrier concentration profiles obtained by the stripping and Van der Pauw techniques indicates that no diffusion of the implanted ions takes place.
Photoacoustic study of laser damage in thin films
Authors: Rosencwaig Allan , Willis J. B.
Published: February 2003

We have developed a photoacoustic method that is capable of detecting the occurrence of laser damage in optical thin films and of providing new data about energy transfer processes in the presence of damage.
The role of cesium suboxides in low-work-function surface layers studied by x-ray photoelectron spectroscopy: Ag-O-Cs
Authors: Yang Sheng-Jenn , Bates Clayton W.
Published: February 2003

The oxidation of cesium on silver substrates has been studied using photoyield measurements and x-ray photoelectron spectroscopy. The occurrence of two O1s peaks in the core-level spectrum at 527.5 and 531.5-eV binding energy for cesium and oxygen exposures giving the optimum photoyield proves that two oxides of cesium exist in high-photoyield surfaces, and not Cs2O alone as previously thought. From the shape and position of the cesium peaks and the Auger parameter, the assignment of the O1s peaks at 527.5- and 531.5-eV binding energies to oxygen in Cs2O and Cs11O3, respectively, can be made. Hence the total cesium-oxygen layer is a mixed phase consisting of Cs2O+Cs11O3, approximately 20–40 Å thick.
Effect of disorder on the hydrogen content in Si+
Authors: Peercy P. S. , Stein H. J. , Ginley D. S.
Published: February 2003

Hydrogen concentrations in disordered silicon were measured after exposure to a low-energy hydrogen rf discharge plasma at temperatures between 300 and 425 °C. The saturation hydrogen concentration is found to increase with disorder until amorphization is reached, whereupon the hydrogen content decreases. These results demonstrate that the amorphous structure cannot be considered as a simple extension of a highly defected crystalline structure. We further find that the hydrogen in a-Si exposed to atomic hydrogen in a plasma is bonded only in the monohydride site with an infrared absorption band at ν=1985 cm−1.
Two-dimensional hole gas at a semiconductor heterojunction interface
Authors: Störmer H. L. , Tsang W.-T.
Published: February 2003

We report the first observation of a two-dimensional hole gas (2DHG) at a semiconductor heterojunction interface (GaAs/AlxGa1−xAs). Low-temperature angular-dependent Shubnikov-de Haas measurements demonstrate the two dimensionality of the system and yield a carrier surface density of 7×1011 cm−2. From the temperature dependence of the magneto oscillations we derive an effective mass of 0.35±0.1m0 for the carriers. Hall measurements establish a He temperature mobility of μ≈1700 cm2/V sec.
Amorphous-silicon thin-film metal-oxide-semiconductor transistors
Authors: Hayama Hiroshi , Matsumura Masakiyo
Published: February 2003

Two types of glow-discharged amorphous-silicon thin-film metal-oxide-semiconductor field-effect transistors (MOSFET’s) were fabricated. The N-channel enhancement-type FET, which has an undoped channel region, showed only a few hysteresis characteristics and, by changing the gate voltage, the drain current was changed from the order of pA to the order of 0.1 μA at Vd=20 V. The FET, which has a doped n layer at the channel region, operated in the depletion mode and its on-current was changed by changing the doping-gas concentration. It seems that the FET’s have various potential applications, especially for switching circuits used for display devices.
The solid solubility and thermal behavior of metastable concentrations of As in Si
Authors: Lietoila A. , Gibbons J. F. , Sigmon T. W.
Published: February 2003

The solubility of As in Si as an active, noncomplexed dopant is determined by completely activating with laser annealing a metastable As concentration of about 1×1021/cm−3, and subjecting it to thermal-equilibrium annealing. The solubility is 9.3×1019 cm−3 at 700 °C and 3.2×1020 cm−3 at 1000 °C. MeV ion channeling measurements show that when As deactivation from the metastable concentration takes place at 900 °C, the As atoms stay almost completely substitutional. The deactivation process has a thermal activation energy of 2.0 eV at 350–410 °C.
Large growth-induced anisotropy to preferential occupation of the iron sites in garnets
Authors: Luther L. C. , LeCraw R. C. , Gyorgy E. M. , Blank S. L.
Published: February 2003

Large growth-induced anisotropies (Ku) arising from the preferential occupation of Ir4+ on octahedral sites have been measured. For YIG with approximately 0.2 Ir atoms per garnet formula unit and Mg2+ as a charge compensator, values of Ku=+4.5×105 ergs/cm3 have been obtained. The induced anisotropy is proportional to the Ir4+ present as deduced from the optical absorption.
Lifetime extension of XeCl and KrCl lasers with additives
Authors: McKee T. J. , James D. J. , Nip W. S. , Weeks R. W. , Willis C.
Published: February 2003

The stabilization and extension of operation of XeCl (308 nm) and KrCl (222 nm) excimer lasers by the addition of very low concentrations of hydrogen gas is described. Lifetime extension of a sealed-off XeCl laser operating at 8 W and 150 Hz is reported, with more than three million shots to half power. Spectroscopic analysis of the laser gas indicates a large reduction in a discharge-induced absorption feature below 230 nm; no absorption is observed at 308 nm.
Effect of neutron irradiation on the pulse dispersion in a step-index optical fiber
Authors: Rao R. , Mitra S. S.
Published: February 2003

Neutron-radiation-induced pulse dispersion changes were measured in a 100-μ step-index fiber. These results are presented with a discussion of mechanisms by which dispersion changes due to radiation can occur. The results also give information on the radiation-induced attentuation in fibers.
Computer modelling study of ablative optical recording
Authors: Cohen M. S.
Published: February 2003

Computer modelling is used to study both the optical and thermal behavior of ablative optical storage media which consist of antireflection structures incorporating a thin active layer. Confirmation is given of Blom’s contention that the advantages of improved optical efficiency gained by use of antireflection structures can be lost by heat losses to the mirror layer underlying the active layer. However, this efficiency can be regained if the dielectric spacer between these two layers is made thick enough or has sufficiently low thermal conductivity.
A Josephson ultrahigh-resolution sampling system
Authors: Tuckerman David B.
Published: February 2003

An ultrahigh-resolution Josephson-technology sampling system has been designed and tested. A complex test signal containing a 10-ps rise time was measured and agreed very well with the signal expected from simulations. The intrinsic rise time (step response) of the sampling system is believed to be about 6 ps. External analog circuitry was used to automate the system.
An applied-Bθ magnetically insulated ion diode
Authors: Greenspan M. A. , Pal R. , Hammer D. A. , Humphries S.
Published: February 2003

A new magnetically insulated ion diode geometry has been developed for use on a 270-kV, 3.3-Ω, 80-ns pulse line. A proton beam is extracted at ∼100 A/cm2 with a divergence angle of ≲ 2°(full-width half angle), and focused to over 600 A/cm2. Magnetic insulation is provided by a current flowing through a conductor on the axis of the diode in the same direction as the ion beam.
Charge trapping in plasma-polymerized thin films
Authors: Klemberg-Sapieha J. E. , Sapieha S. , Wertheimer M. R. , Yelon A.
Published: February 2003

The surface potential of freshly plasma-polymerized films of hexamethyldisiloxane was measured for film thicknesses ranging from about 0.1 to 1 μm. The films are found to be in an electret state under certain fabrication conditions. Experimental evidence is given which indicates that charge trapped during plasma polymerization is uniformly distributed across the sample thickness. It has been found that other electret properties such as the polarity of trapped charge, and the charge retention characteristics can also be controlled by an appropriate choice of polymerization conditions.
Reduction of GaAs diode laser spontaneous emission
Authors: Streifer W. , Ponce F. A. , Scifres D. R.
Published: February 2003

Spontaneous emission from GaAs lasers is substantially reduced by fabricating a high-reflection dielectric stack coating for the rear facet and apertured coatings of highly absorbing Te for the front (output) facet. After deposition the Te is ablated by the laser mode itself and the aperture is stabilized by Al2O3 overcoating. The stimulated emission at mode center passes through the aperture unattenuated, whereas the spontaneous emission at the edges of the mode is strongly absorbed. Since spontaneous emission at mode center saturates above threshold we estimate that the ratio of stimulated to spontaneous power will approach 100 at near-10-mW output levels.
An optical TE-TM mode splitter using a LiNbO3 branching waveguide
Authors: Masuda Masamitsu , Yip Gar Lam
Published: February 2003

A novel optical TE-TM mode splitter using a Ti-diffused branching waveguide in Y-cut LiNbO3 is proposed and demonstrated. Mode splitting has been confirmed experimentally at an applied voltage V0=−20 V.
Optically pumped laser action at 77 K in GaAs/GaInP double heterostructures grown by molecular beam epitaxy
Authors: Scott G. B. , Roberts J. S. , Lee R. F.
Published: February 2003

cw laser action has been achieved at 77 K in double heterostructures of GaAs/Ga0.47In0.53P grown by molecular beam epitaxy using the dimers P2 and As2. The 6471-Å line of a krypton laser was used to optically pump 100-μm-wide bars of the p isotype structure having an active region thickness of 0.25 μm. Laser action was initiated, as witnessed by the appearance of Fabry Perot modes in the emission and the occurence of a sharp knee in the emitted-power–pump-power characteristic, at an absorbed power density of 103 W/cm2.
Confining substrate for micron-thick liquid films
Authors: Kuech T. F. , McCaldin J. O.
Published: February 2003

Suitable combinations of surface geometry and material enable a substrate to hold a thin liquid film captive on its surface. Though only at metastable equilibrium, such films can survive a moderate amount of processing. They may be suited to the growth of semiconductor single-crystal films on amorphous substrates.
Laser annealing under the oxide layers in silicon
Authors: Narayan J.
Published: February 2003

Laser pulses have been used to study the growth and removal of dislocations underneath thin oxide layers in silicon. These observations provide clear evidence of melting under the oxide layer without disturbing the oxide layer on the surface. The thickness of melted regions increased with increasing of stacking faults were observed, presumably as a result of melting of the oxide layer and the introduction of oxide clusters in silicon.
High-sensitivity InGaAsP/InP phototransistors
Authors: Tobe M. , Amemiya Y. , Sakai S. , Umeno M.
Published: February 2003

InGaAsP/InP phototransistors have been fabricated using the liquid phase epitaxy technique. In spite of the early stage of development, the fabricated detectors exhibited a current gain of more than 103 and rise time of about 50 nsec. With further development, InGaAsP/InP phototransistors will become promising detectors for optical communication systems in the 1.0–1.7-μm spectral region.
Efficient indium tin oxide/polycrystalline silicon semiconductor-insulator-semiconductor solar cells
Authors: Genis A. P. , Smith P. A. , Emery K. , Singh R. , DuBow J. B.
Published: February 2003

Using neutralized-ion-beam sputtering, high-efficiency (10.94%, AM1) and large-area (total area, 11.46 cm2) indium tin oxide/polycrystalline silicon semiconductor-insulator-semiconductor solar cells have been fabricated. The important steps in the fabrication are the proper surface preparation and the incorporation of hydrogen during milling and oxidation of the substrate. The photovoltaic conversion parameters were Voc =0.526 V, Jsc =27.39 mA/cm2, and FF=0.759.
Effect of substrate temperature on the formation of shallow silicide contacts on Si using Pd-W and Pt-W alloys
Authors: Eizenberg M. , Ottaviani G. , Tu K. N.
Published: February 2003

We have investigated the effect of substrate temperature on the reaction between Si and Pd-W and Pt-W alloys by I-V measurement of Schottky barrier height. We found that by maintaining a substrate temperature of 100 °C during the deposition of W-rich Pd20W80 alloys, Schottky contacts of Pd2Si on Si can be obtained without any subsequent annealing. Similarly, a substrate temperature of 300 °C enables the formation of PtSi during the depostion of W-rich Pt20W80 alloys. For Pd-rich Pd80W20 and Pt-rich Pt80W20 alloys, the substrate-temperature effect is not as significant as for the W-rich alloys.
Thermal-wave microscopy with electron beams
Authors: Brandis Elmar , Rosencwaig Allan
Published: February 2003

We have performed high-resolution thermal-wave microscopy of surface and subsurface features of an opaque solid using, for the first time, electron beams to generate the signal.
Effect of laser light on the sticking coefficient in ZnS thin-film growth
Authors: Arnone C. , Daneu V. , Riva-Sanseverino S.
Published: February 2003

Some preliminary results are presented concerning an effect of laser light (λ=4880 Å) on the growth of an evaporated ZnS film. We observe an increase in thickness in the region of the film illuminated by laser light. The spatial resolution is high and the observed phenomenon is not thermal in origin. A simple and unique method for investigating the dynamics of the effect during its evolution is described.
A high-speed Si lateral photodetector fabricated over an etched interdigital mesa
Authors: Chen C. W. , Gustafson T. K.
Published: February 2003

A new kind of high-speed photodetector has been constructed utilizing the anisotropic etching technique. It is demonstrated that, functioning as an edge-incident photodiode, the detector responds reliably to subnanosecond light pulses with 40% overall quantum efficiency. And, functioning as a phototransistor, it responds to cw radiation with a current gain. Compatibility with existing planar processing is another feature. Possible mechanisms involved are discussed.
Statistical characterization of the self-induced intensity modulation exhibited by AlGaAs junction lasers with proton stripes
Authors: Paoli Thomas L.
Published: February 2003

Results of a statistical study of the self-induced modulation present in the intensity emitted by stripe-geometry (AlGa)As junction lasers are reported. The data indicate that narrowing the width of the proton-delineated stripe from 12 to 8 μm substantially reduces the fraction of unaged lasers with modulation depths greater than about 40% and increases the minimum frequency at which self-induced intensity modulation occurs. Further analysis of the statistical data also suggests that the epi-growth system can play a significant role in determining the statistical distribution of the self-induced modulation depth.
Improvement of the room-temperature behavior of metal tritides with respect to 3He release: Titanium
Authors: Bach Pierre
Published: February 2003

In aged titanium tritide Ti 3 Hex thin films the 3He local critical concentration is slightly technology dependent and appears not to depend on the initial overall tritium concentration for x values lower than 1.5, which in fact results from a two-phase system: Ti and Ti 3H1.5. As it is not possible to increase significantly the lifetime of titanium tritide films by simply lowering their tritium concentration, a different method is proposed, based on deutero-tritide films. This method can be extended to other tritides. Experimental values of 3He critical concentration in aged Ti 3Hx thin films are also determined.
Feedback-induced line broadening in cw channel-substrate planar laser diodes
Authors: Miles R. O. , Dandridge A , Tveten A. B. , Taylor H. F. , Giallorenzi T. G.
Published: February 2003

The effect of optical feedback on the spectral characteristics of channel-substrate planar single-mode laser diodes operating at room temperature is reported. The impact on the performance of interferometric sensor systems using such sources is discussed. The linewidth for the free-running laser at 10-mW output power was determined to be less than 5 MHz at room temperature. Broadening on the order of 40 times the intrinsic linewidth was observed for 0.1% feedback and increased with increasing feedback. The presence of self-oscillation modes was observed at 0.04% feedback. Satellite modes symmetrically located with respect to the primary mode appeared in the spectrum for feedback greater than 0.04%. These satellite modes are attributed to self-oscillation in the laser induced by feedback. As the feedback was increased, the satellite mode spectrum began to overlap that of the primary mode, reducing the effective coherence length from 60 m (for the single-mode linewidth) to less than a few centimeters.
Surface acoustic wave characteristics of a single crystal of potassium lithium niobate
Authors: Takeuchi Hiroshi , Yamashita Kunio
Published: February 2003

The surface acoustic wave (SAW) characteristics of a single crystal of potassium lithium niobate K2.98Li1.55Nb5.11O15 are calculated using published data. It is found that there are two sets of propagation planes and directions having zero temperature coefficient of SAW delay time. One set has a large electromechanical coupling factor (K2s=0.9%) and a zero power flow angle. The temperature stability of this crystal is located between that of T13TaSe4 and ST-cut quartz.
Nucleation-controlled overgrowth of silicon on silica
Authors: Leamy H. J. , Doherty C. J.
Published: February 2003

We have demonstrated the nucleation-controlled overgrowth of silicon single crystals on an oxidized silicon wafer. The crystals are grown from an Al-Si liquid film by nucleation at via holes in the oxide substrate.
Intensity-dependent absorption in semiconductors
Authors: Stewart Alan F. , Bass Michael
Published: February 2003

Laser calorimetry has been used to study intensity-dependent absorption processes in semiconductors at 1.06 and 1.318 μm. New measurements of two-photon absorption and two-photon-excited free carriers are reported. Saturation of the one-photon absorption has been observed and evidence is presented for a pulse width dependence of the two-photon absorption.
Ion backscattering and channeling study of InAs-GaSb superlattices
Authors: Saris F. W. , Chu W. K. , Chang C. A. , Ludeke R. , Esaki L.
Published: February 2003

We show that the Rutherford backscattering yield from [100] InAs-GaSb superlattices has a marked oscillatory structure indicative of the superlattice periodicity. Channeling measurements reveal higher dechanneling along 〈110〉 than along [100] directions, and this can be interpreted as an evidence for relaxation effects along the [100] growth direction at each InAs-GaSb interface. We attribute this to the fact that, although there is a good lattice match between InAs and GaSb, the interfaces consist of either Ga–As or In–Sb bonds, which differ by 7% in binding distance from InAs-GaSb.
Phase formation in Cr-Si thin-film interactions
Authors: Colgan E. G. , Tsaur B. Y. , Mayer J. W.
Published: February 2003

Silicide formation has been studied in Cr-Si thin-film samples by MeV 4He+ backscattering and glancing-incidence x-ray diffraction. Samples of SiO2/Cr/Si configuration were prepared by sequential e-gun deposition of Cr and Si onto SiO2 substrates with the relative film thicknesses adjusted to Cr:Si ratios of 3.0 (Cr3Si), 1.67 (Cr5Si3), and 1.0 (CrSi). In the early stage of phase formation when both unreacted Cr and Si are present, the CrSi2 phase is formed. The phase grows until the Si is completely consumed, and then a metal-rich phase, Cr5Si3, is formed at the Cr-CrSi2 interface. Upon further heating of samples with a Cr:Si ratio of 3.0, Cr5Si3 reacts with Cr to form a more Cr-rich phase, Cr3Si. The CrSi phase was observed only in samples with a Cr:Si ratio of 1. All the compounds present in the phase diagram were observed. The end phases are determined by the availability of Cr and Si in the reactions and can be predicted from the phase diagram.
Modification of Schottky barrier height by surface grain boundaries of polycrystalline silicon
Authors: Wu C. M. , Yang E. S.
Published: February 2003

It is found that the Schottky barrier height φBn depends on the grain-boundary surface state density DBS and the boundary density dB, which is defined as the length of grain boundary on the surface per unit area (inversely proportional to the average grain size). Experimental data for Au–polycrystalline-Si (n type) Schottky diodes indicate that the effective grain-boundary state density is approximately 3×1011 cm−1 eV−1 and the change of barrier height is consistent with the proposed model.
Twin-stripe injection laser with leaky-mode coupling
Authors: Ackley D.E. , Engelmann R.W.H.
Published: February 2003

A new twin-stripe leaky-mode (TLM) injection laser has been demonstrated. The structure consists of two nominally 2-μm-wide stripes on 24-μm centers in a buried-heterostructure configuration (produced by mesa-etching a three-layer double heterostructure and burying with an AlGaAs layer). By adjusting the mole fraction of Al in the burying layer, a negative-index step is produced at the lateral stripe boundary. Thus a substantial fraction of laser power leaks into the low-loss waveguide region between the stripes, and strong stripe coupling is observed. The far field consists of two collimated (divergence ∼1°) beams characteristic of leaky-mode operation that are stable to pulsed drive current as high as 6Ith. Linear output characteristics are observed to powers greater than 150 mW.
Above-threshold analysis of double-heterostructure diode lasers with laterally tapered active regions
Authors: Streifer W. , Scifres D. R. , Burnham R. D.
Published: February 2003

An above-threshold analysis of double-heterostructure lasers with laterally tapered active regions is presented. Results for lowest-order mode threshold, differential quantum efficiency, and higher-order transverse-mode threshold are shown to compare well with experimental observations. A design is presented for a 40-mA-threshold laser (275 μm in length) predicted to operate kink free, single transverse mode at ≈50% differential quantum efficiency up to ≈40 mW.
Optical bistability using a directional coupler and a detector monolithically integrated in GaAs
Authors: Carenco A. , Menigaux L.
Published: February 2003

An electro-optic directional coupler has been integrated on the same GaAs chip with a proton-implanted detector located in one of the output rib waveguide channels. The association of this monolithic device with an external electrical amplifier has allowed optical bistable operation to be demonstrated at 1.06 μm. With an amplifier gain equal to unity, the bistable device switches in about 1 μs, the optical switching energy being less than 1 nJ.
Optical impedance spectroscopy
Authors: Stanciulescu C. , Bobulescu R. C. , Surmeian A. , Popescu D. , Popescu Iovitzu , Collins C.B.
Published: February 2003

A generalized technique of impedance spectroscopy is implemented through the detection of perturbations measured at radio frequencies in the electromagnetic impedance of a medium. The perturbations are caused by the absorption of optical photons. At low powers this offers a complementary method to existing schemes in optical spectroscopy that can be used with high sensitivity. In the limit of high powers it becomes equivalent to optogalvanic spectroscopy with several important advantages.
Field effect measurement on the film-substrate and film-vacuum interfaces of a-Si:H
Authors: Guha S. , Narasimhan K. L. , Navkhandewala R. V. , Pietruszko S. M.
Published: February 2003

Field effect experiments on a-Si:H films at the bottom (film-substrate interface) and the top (film-vacuum interface) of the film are reported. Because of the presence of an absorbate at the top surface, the field effect at the top is found to be much smaller than at the bottom. After a heat treatment at 175 °C for two to four hours, the field effect at the top and the bottom are found to be similar.
Elastic rubber-waveguide geodesic optical deflector
Authors: Johnson Mark
Published: February 2003

A novel technology for fabricating multimode thin-film optical components is described. Light is guided within a nonplanar transparent rubber film, following geodesics of the film surface. Controlled deformation of the surface through mechanical or pneumatic forces makes possible mode- and wavelength-independent focusing, deflecton, and switching.
Overshoot switching, alternate switching, and subharmonic generation in bistable optical devices
Authors: Goldstone J. A. , Ho P.-T. , Garmire E.
Published: February 2003

We demonstrate both experimentally and theoretically a new mode of transient switching using rapid-onset light signals in a bistable optical device with two comparable time constants. Four distinct transmission modes for input pulse trains have been observed, one of which produces a subharmonic of the input pulse train by alternate overshoot switching.
Interface transduction in the ZnO-SiO2-Si surface acoustic wave device configuration
Authors: Melloch M. R. , Gunshor R. L. , Liu C. L. , Pierret R. F.
Published: February 2003

Results are presented describing the operational behavior of a ZnO-SiO2-Si surface acoustic wave (SAW) device with a new transducer configuration. In the new configuration the transducer is positioned at the ZnO-SiO2 interface; a metal overlays the transducer at the outer ZnO surface. The transduction loss in a SAW delay line is observed to vary by 30 dB when a dc voltage is applied to the interface transducer. This change in transduction with bias is cited as the basis for the possible construction of a new class of programmable devices. The lowest measured insertion loss is 20 dB, a value comparable to that obtained from conventional ZnO-SiO2-Si devices.
Dependence of the electrical characteristics of heavily Ge-doped GaAs on molecular beam epitaxy growth parameters
Authors: Metze G. M. , Stall R. A. , Wood C. E. C. , Eastman L. F.
Published: February 2003

Ge incorporation into molecular beam epitaxial GaAs as a function of substrate temperature (350–620 °C), Ge flux (109–1014 cm−2 sec−1) and of As4/Ga flux ratio (10/1) has been studied. The free-electron (7.4×1019 cm−3) and free-hole (3.0×1020 cm−3) concentrations in GaAs were the highest obtained to date. Tentative incorportion mechanisms for Ge in GaAs are also presented.
Interface grading in InGaAsP liquid phase epitaxial heterostructures
Authors: Cook L. W. , Feng M. , Tashima M. M. , Blattner R. J. , Stillman G. E.
Published: February 2003

Auger depth profiles on InGaAs-InP and InGaAs-InGaAsP heterojunctions grown by liquid phase epitaxial (LPE) techniques have been measured. For InGaAs-InP and InGaAsP-InGaAs-InGaAsP heterostructures where the lattice mismatch Δa/a between the grown layers is less than ±0.03%, the chemical transition width of the InGaAs-InP and InGaAs-IGaAsP interfaces (the last-grown layer is listed first) is less than 90 Å, the depth resolution capability of the Auger microprobe in these measurements. In contrast, the chemical transition width of the lattice-matched InGaAsP-InGaAs interface is significantly larger than this. This increased transition width results from significant dissolution of the InGaAs epitaxial layer by the InGaAsP growth solution which is controlled by the diffusion of As from the interfacial region. These results suggest that it may be impossible to avoid grading at LPE InP-InGaAs interface.
Lattice defects in As-implanted and cw Nd:YAG laser-annealed silicon
Authors: Ishida K. , Okabayashi H. , Yoshida M.
Published: February 2003

Lattice defects in As-implanted and cw Nd:YAG laser-annealed silicon have been studied. Observed defects are small point defect clusters at lower laser power which develop into dislocation loops at higher laser power. Further increase of laser power results in annihilation of the dislocation loop, but with generation of slip dislocations owing to large thermal stress. The mechanism of the dislocation loop annihilation is considered to be due to dislocation climb motion as in the case of usual thermal annealing.
Cyclotron resonance and the magnetophonon effect in GaxIn1−xAsyP1−y
Authors: Nicholas R. J. , Sessions S. J. , Portal J. C.
Published: February 2003

Cyclotron resonance and the magnetophonon effect have been used to measure the effective mass as a function of alloy composition for GaxIn1−xAsyP1−y samples grown lattice matched to InP. Values of ωτ of up to 6 allow an accurate measurement of effective mass, which is found to depend linearly upon alloy composition y with the relation m*/m0=0.080−0.039y. The observation of shallow impurity transitions in a quaternary alloy is also reported.
High-gain InGaAsP-InP heterojunction phototransistors
Authors: Wright P. D. , Nelson R. J. , Cella T.
Published: February 2003

InGaAsP-InP heterojunction phototransistors have been fabricated by liquid phase epitaxy. The phototransistors have optical gains greater than 100 for 1.26-μm radiation. High internal current gains (≳300) have been achieved. Phototransistor relative spectral response has been measured for wavelengths in the range 0.7–1.5 μm.
Evidence for partial solid-state regrowth during pulsed-laser annealing
Authors: Gibson J. M. , Tsu R.
Published: February 2003

Nonsecond pulsed-laser annealing of semiconductors is widely believed to be a simple thermal melting and recrystallization effect. We have examined subthreshold-irradiated arsenic-implanted silicon wafers in cross section by conventional transmission and scanning transmission electron microscopy. Both microdiffraction and high-resolution microscopical techniques were found to be very useful. There is evidence for both thermal melting and at a deeper level partial solid-state regrowth. The origin of this nucleation is thought to be thermal but it may be influenced by ionization or stress effects.
Near-band-gap photoluminescence of Hg1−xCdxTe
Authors: Hunter A. T. , Smith D. L. , McGill T. C.
Published: February 2003

The results of photoluminescence studies of Hg1−xCdxTe with x=0.32 and 0.48 for temperatures between 5 and 30 K are described. In the x=0.32 and x=0.48 material, band-to-band, band-to-acceptor, and donor-to-acceptor luminescence lines are observed. We report the first observation of bound-exciton luminescence in HgCdTe, which we observe in the samples with x=0.48.
Double heteroepitaxy in the Si (111)/CoSi2/Si structure
Authors: Saitoh Shyuichi , Ishiwara Hiroshi , Furukawa Seijiro
Published: February 2003

Epitaxial growth of CoSi2 films on Si substrates and the growth of Si films on the Si(111)/CoSi2 structure are investigated. Solid phase epitaxy is used to grow both CoSi2 and Si films. Molecular beam epitaxy is also used to grow the top Si films in the double heteroepitaxy. It has been found that two dominant factors required to obtain good epitaxial films are substrate cleaning by lamp heating before the film deposition and annealing of the deposited films without exposure to air. Excellent crystalline quality of the CoSi2 films on (111) Si substrates and good quality of the Si films on the Si(111)/CoSi2 structure have been demonstrated by ion channeling and backscattering techniques and reflection electron diffraction analysis. Uniformity of the grown films has also been examined by scanning electron microscopy.
Shallow silicide-to-silicon contacts: The case of amorphous-Pd80Si20–to–silicon
Authors: Kritzinger S. , Tu K. N.
Published: February 2003

It is known that fabrication of shallow silicide-to-silicon contacts is possible by diluting the silicide-forming metal with some other metal which does not participate in silicide formation at the chosen annealing temperature. We report preliminary experiments undertaken to develop contacts which are even shallower, by a modification of this method. The diluting metal is replaced by Si which supplies a portion of the Si needed in silicide formation. An amorphous alloy of ∼400-Å Pd80Si20, coevaporated onto a Si single crystal substrate, has been successfully used to form a continuous and uniform layer of Pd2Si which only consumes ∼80Å of substrate silicon. The formation and microstructural properties of the formed silicide has been studied by in situ transmission electron microscopy experiments. These results were correlated with parallel measurements of the current-voltage characteristics of Schottky diodes made from the same material. It is shown that annealing for ∼ 1/4 h at 200 °C is sufficient to form the desired Pd2Si.
Light-induced effects in Schottky diodes on hydrogenated amorphous silicon
Authors: Jousse D. , Basset R. , Delionibus S. , Bourdon B.
Published: February 2003

An exposure of Schottky diodes on hydrogenated amorphous silicon (a-SiH) for several hours to light (AM1) reduces by a factor of 4 the dark forward current at V=1 V as well as the photocurrent under low illumination. Annealing above 150 °C partly reverses the process. Current-voltage measurements versus temperature show a shift of the bulk Fermi level of about 80 mV from the conduction band due to the increasing of the density of states in the midgap of a-SiH as can be seen from capacitance-voltage measurements. We explain the surprising stability of the photovoltaic functioning by the trapping of photogenerated holes which acts as an optical doping of the material.
Effect of Si dissolution and recrystallization upon ohmic Al/p-Si contacts
Authors: Dascălu D. , Brezeanu Gh. , Dan P. A.
Published: February 2003

The electrical behavior of a sintered Al/p-Si ohmic contact is evaluated by means of a new computer fitting technique, the diameter perturbation method. Both the specific contact resistance and the semiconductor resistivity are accurately determined. The effect of sintering temperature and duration is explained by the presence of a nonuniform recrystallized surface layer (Si doped with Al atoms). Certain hypotheses are confirmed by scanning electron micrographs.