bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Direct Current on Precipitation in Quenched Al + 4% Cu Thin Films
Authors: Shine M. C. , Herd S. R.
Published: January 2004

Resistance changes associated with precipitation in Al–Cu thin films were monitored during power annealing at current densities up to 4×106 A/cm2 and temperatures of ∼178 and 200 °C. The rate of change of resistance decreased as the current increased. It is argued that this decrease is due to the current inhibiting the precipitation of θ Al2Cu.
Picosecond Electron-Optical Chronography
Authors: Bradley D. J. , Liddy B. , Sibbett W. , Sleat W. E.
Published: January 2004

An image-tube streak camera has been further developed to be completely electronically operated, with an improved instrumental time resolution of <4 psec and negligible background. With a trigger pulse of 10 V and a rise time of 1 nsec, the over-all system triggering jitter is <200 psec. The camera has been used to measure the durations of ultrashort pulses (2–3 psec) from a mode-locked dye laser.
Optical Second-Harmonic Generation in Paratellurite and Kleinman's Symmetry Relations
Authors: Chemla D. S. , Jerphagnon J.
Published: January 2004

The second harmonic of a 1.064-μ Nd3+ YAG laser has been observed in paratellurite This effect is forbidden by Kleinman's relations. The only nonvanishing nonlinear coefficient d14 has been measured relative to quartz by the Maker-fringe technique and to KDP under phase-matching conditions. It has been inferred that d14=1.4×10−9 esu and δ14=3.8×10−8 esu. The latter value is 40 times lower than the average over all the known materials.
Magnetic-Field-Dependent Breakdown of CO2-Laser-Produced Plasma
Authors: Cohn D. R. , Chase C. E. , Halverson W. , Lax B.
Published: January 2004

The threshold pressure for breakdown of helium and argon gas by 10.6-μm radiation from a TEA CO2 laser is strongly depressed by a steady magnetic field parallel to the direction of propagation of the laser beam. At 87 kOe, the zero-field threshold pressure is reduced from 166 to 96 Torr in helium and from 66 to 21 Torr in argon. This result can be explained semiquantitatively by a simple model of breakdown that takes into account the inhibition of radial electron diffusion by the magnetic field.
Mg–O Complexes in GaP—A Yellow Diode
Authors: Bhargava R. N. , Michel C. , Lupatkin W. L. , Bronnes R. L. , Kurtz S. K.
Published: January 2004

A yellow-orange luminescence which peaks at 6030 Å at 300 °K has been observed in (Mg, O)-doped GaP and is attributed to a bound excitonic transition at a nearest-neighbor Mg–O complex. A photoluminescent efficiency at low temperatures of ∼20% has been measured and yellow diodes of external quantum efficiency ≃0.1% at 77 °K have been fabricated.
Effect of Proton Bombardment on Pb0.76Sn0.24Te
Authors: Tao T. F. , Wang C. C. , Sunier J. W.
Published: January 2004

Effects of 200–450-keV proton bombardment on the electrical properties of Pb0.76Sn0.24Te were studied. p-type samples of initial hole concentration in the low 1017/cm3 range were converted to n type after a proton dose of 5 × 1013 p/cm2. For samples of higher initial hole concentration, the conversion was less consistent. The change in mobility due to bombardment was found to be moderate. The mobilities of some p-type samples were doubled after type conversion.
Beam Effects in the Analysis of As-Doped Silicon by Channeling Measurements
Authors: Rimini E. , Haskell J. , Mayer J. W.
Published: January 2004

Channeling-effect measurements with MeV He ions have been used to study the lattice location of As in silicon. Over the concentration range studied (5 × 1019 − 1.2 × 1021/cm3) As was found to be 90–95% on substitutional sites. However, it was found that bombardment with the analysis beam caused 20–40% of the As to move off lattice sites. This effect may be responsible for the relatively low As substitutional fraction found in previous investigations. No bombardment-induced off-lattice movement was found in Sb-doped Si indicating that this movement is species dependent.
Optical Transmission in Liquid-Core Quartz Fibers
Authors: Stone J.
Published: January 2004

Multimode liquid-core quartz fibers, potentially useful for long-distance optical communication, have been constructed. The optical transmission loss of these fibers has been measured between 6000 and 11 000 Å. Fibers filled with tetrachloroethylene or a mixture of equal parts by volume of tetrachloroethylene and carbon tetrachloride have transmission loss of 20 dB/km or less between 8400 and 8600 Å and between 10 400 and 11 000 Å. These bands are of particular interest because within them operate highly promising oscillators such as the GaAs diode and the Nd: YAG laser. An absorption peak of 80 dB/km at 9600 Å is attributed to a small percentage of OH in the tetrachloroethylene. In the wavelength intervals between 7000 and 7600 Å and between 8200 and 11 000 Å these fibers have losses lower than or about equal to those reported for any other fibers.
New Thin-Film Tunnel Triode Using Amorphous Semiconductors
Authors: Shaw R. F. , Fritzsche H. , Silver M. , Smejtek P. , Holmberg S. , Ovshinsky S. R.
Published: January 2004

A new thin-film tunnel triode is discussed which uses a p-type amorphous film to achieve amplification of injected current from a tunnel cathode. It is not only the basis for a new semiconductor device but also suggests a novel method for measuring electrical properties of semiconductors.
CO Laser Action by C2H2 Oxidation
Authors: Barry J. D. , Boney W. E. , Brandelik J. E. , Mulder D. M. , Woessner J. K.
Published: January 2004

Laser emission has been detected from CO molecules produced by the dc discharge-initiated chemical oxidation of C2H2. The vibrational-rotational transitions were P branch from v = 3:2 to v = 11:10 with J = 11−14, nominally. The explosive property of the oxidation reaction was verified.
Bistable Switching in Metal-Semiconductor Junctions
Authors: Moser A.
Published: January 2004

Bistable switching with memory has been achieved in various n-type GaAs Schottky contacts and n-type Si Schottky contacts doped with trap impurities. Transition from the low-conductivity state into a high-conductivity state is established after a delay of 10 nsec, when a threshold voltage is exceeded. With opposite bias direction, resetting occurs in 10 nsec by exceeding a current threshold. Either state is maintained over weeks without bias.
High-Field Transport Properties of GaSb
Authors: Ruch J. G.
Published: January 2004

The recent availability of experimental data on the hot-electron transfer in GaSb has stimulated the present theoretical work. In the past, the only comparison between hot-electron transport theory and experiment has been through the velocity-field characteristic or galvanic-magnetic phenomena. Because of the insensitivities of these macroscopic characteristics to the value of the deformation potential for nonequivalent intervalley scattering, an exact value for the latter, which governs the electron transfer between central and satellite valleys, could not be obtained. A Monte Carlo calculation has been used to obtain the deformation potential for nonequivalent intervalley scattering by interpreting the experimental data on hot-electron transfer in GaSb obtained using the Faraday rotation.
Behavior of Phosphorous and Arsenic Diffused Simultaneously into Silicon Crystals
Authors: Fujimoto F. , Komaki K. , Watanabe M. , Yonezawa T.
Published: January 2004

Behavior of phosphorus and arsenic atoms diffused simultaneously into silicon crystals, in which the density of phosphorus at the surface is 1021 cm−3, was studied by random and aligned spectra of backscattered helium ions and radioactive analysis techniques. It was concluded that the phosphorus atoms enter substitutionally and arsenic atoms interstitially, indicating that interstitial atoms inhibit the generation of dislocations.
The Use of Sm3 Co in Sintering SmCo5 Magnets
Authors: Carriker R. C.
Published: January 2004

The use of single phase Sm3Co as a sintering aid in the liquid-phase sintering of SmCo5 has been investigated. The magnetic properties of this system were studied as a function of the sintering-aid content and sintering time vs temperature. Using a modest alignment field of only 10 kOe, a magnet with an energy product of 17.0 MG Oe has been achieved.
Josephson Junctions with Nb/Al Composite Electrodes
Authors: Laibowitz R. B. , Mayadas A. F.
Published: January 2004

Josephson tunnel junctions have been fabricated incorporporating a thin layer of normal metal which is oxidized to form the tunnel barrier. The tunnel devices tested were of the form Nb/Al/Al2O3/Nb and several milliamperes of Josephson current were observed at 4.2°K. These samples have been found to have better defined tunneling characteristics than samples of the form Nb/NbOx/Nb.
Relative Raman Cross Section for O3, CH4, C3H8, NO, N2O, and H2
Authors: Fouche D. G. , Chang R. K.
Published: January 2004

The relative Raman cross sections of gases which are of interest in air pollution studies have been measured at 5145 Å. These relative differential cross sections compared to that of N2 are as follows: O3 (4.0), CH4 (8.0), C3H8 (2.4, 5.8), NO (0.55), N2O (2.7, 0.53), and H2 (2.2). The absolute Raman cross section for N2 has been revised to be (4.4±1.7) × 10−31 cm2/sr at 5145 Å, for vertically polarized input and 90° scattered Raman radiation that is not analyzed for its polarization.
Visible Cathodoluminescence of AgGaS2, a I-III-VI2 Chalcopyrite Compound
Authors: Noblanc J. P. , Loudette J. , Duraffourg G. , Robertson D. S.
Published: January 2004

The cathodoluminescence of AgGaS2, a I-III-VI2 ternary chalcopyrite compound, has been studied in the 2.1–2.8-eV range at 300, 77, and 21 °K. At 300 and 77 °K the annihilation of free excitons is observed, while at 21 °K only extrinsic transitions appear. A study of the polarization shows that the excitonic lines are polarized E ∥ C.
Observation of Film Growth Process by Means of Backscattering Technique
Authors: Meyer O. , Mann H. , Linker G.
Published: January 2004

Evaporated Sn layers on Si and sapphire substrates were used to demonstrate the applicability of the backscattering technique to measurement of the fraction of covered area, the average thickness of the layer, and the sticking factor for temperatures over the range 77–400 °K. The sticking factor at 293°K was found to be ⅓ of that at 77 and 393 °K, and 19% higher at room temperature (r.t.) for Sn on Sn as compared with Sn on Si. At 393 °K the fraction of covered area was found to be about 60% and the average island thickness was in the range 450–1000 Å.
Total Optical Attenuation in Bulk Fused Silica
Authors: Rich T. C. , Pinnow D. A.
Published: January 2004

A survey has been made of optical attenuation in a series of commercially available silica, SiO2, samples to determine the suitability of this material for fiber optical communications. The absorptive component of the attenuation was measured by a precision calorimetric technique, while the scattering component was determined by a new method based on spontaneous Brillouin spectroscopy. Both techniques set an upper limit on the loss and are precise to within a fraction of 1 dB/km. Of the samples tested, the best has a total attenuation of less than 3 dB/km at the 1.06-μ wavelength of the YAlG : Nd laser.
Thin-MIS-Structure Si Negative-Resistance Diode
Authors: Yamamoto Tatsuo , Morimoto Mitsutaka
Published: January 2004

We have realized a high-switching-speed Si S-shaped negative-resistance diode having a thin MIS structure where the thickness of the SiO2 layer is less than 100 Å. It has a p-n-I (insulator)-M (metal) structure in contrast with a Shockley diode. The threshold and sustaining voltages are about 20 and 2–3 V, respectively. The regenerative nature of this device may be related to the minority carrier injection into the interface between the n layer and the insulating layer, and electron trapping in the interface states.
Broadband Superconducting Quantum Magnetometer
Authors: Kamper R. A. , Simmonds M. B.
Published: January 2004

We describe the design, operation, and performance of a superconducting quantum interference device (SQUID) which operates at a frequency of 9 GHz. It is sensitive to variations of magnetic field in a frequency band from 0 to 1 GHz.
Assessment of Tourmaline as an Acoustic-Surface-Wave-Delay Medium
Authors: Lewis M. F. , Patterson E.
Published: January 2004

Measurements and calculations have shown tourmaline to be a useful surface-acoustic-wave-delay medium. In particular, its combination of high velocity and very low propagation losses, together with a moderate piezoelectric coupling strength, makes it suitable for use at higher frequencies than are feasible with quartz or LiNbO3.
Variation of N2-Broadened Collisional Width with Rotational Quantum Number for the 10.4-μm CO2 Band
Authors: Young Charles , Bell R. W. , Chapman R. E.
Published: January 2004

Collisional widths for the individual rotational lines of the P branch of the 10.4-μm CO2 band have been measured using a CO2 laser as the ir energy source. Both self-broadening and N2 broadening have been studied. An anomalously large N2-broadened width in the vicinity of J = 34 has been observed with an indication of a similar effect for the self-broadened width.
p-n Junction Photodiodes in PbTe Prepared by Sb+ Ion Implantation
Authors: Donnelly J. P. , Harman T. C. , Foyt A. G. , Lindley W. T.
Published: January 2004

n-p junction photovoltaic detectors in PbTe have been fabricated using Sb+ ion implantation to create the n-type layer. At 77 °K, 15-mil square diodes have had zero-bias resistances as high as 15 MΩ for a resistance-area product of 2.1×104 Ωcm2. Peak detectivities at 4.4 μm in reduced background as high as 1.6×1012 cmHz1/2/W were observed. Diode quantum efficiencies were typically 40% at 4.4 μm.
Efficient Second Harmonic Generation of Picosecond Laser Pulses
Authors: Rabson T. A. , Ruiz H. J. , Shah P. L. , Tittel F. K.
Published: January 2004

Efficient conversion to the second harmonic (SH) using KD2PO4 and CsH2AsO4 crystals inside a folded cavity of a high-power-dye mode-locked Nd3+: glass laser is reported. For the first time, frequency-doubled picosecond light pulses have been obtained in CsH2AsO4 with peak powers of the order of 109 W/cm2 at 0.531 μ for an effective pump power density of 4×109 W/cm2.
Improved IRQC Performance of CdF2 :Er3+ by Generation of C3ν Local-Site Symmetry
Authors: Byer N. E. , Ensign T. C. , Mularie W. M.
Published: January 2004

Selective generation of trigonal (C3ν) symmetry at Er3+ ions in CdF2 by oxygen firing increases the green (4S3/2→4I15/2) radiative efficiency from 1.9 to 52% while causing qualitative changes in the optical absorption and emission associated with these ions. Measurements of the parameters involved in the operation of an infrared quantum counter suggest that this oxygen-fired material could be used to construct an uncooled infrared detector having a minimum detectable power of 3.6×10−14 W at 1.53 μm, appreciably better than currently available detectors sensitive at this wavelength.
Enhancement of Nonlinearity in Surface-Acoustic-Wave Propagation from Coupling to Charge Carriers
Authors: Lee C. W. , Gunshor R. L.
Published: January 2004

We report the observation of second harmonic generation and acoustic-wave convolution for surface waves on YZ-cut lithium niobate where the nonlinearity originates with the charge-particle dynamics in a nearby semiconductor. The second harmonic generation is 28 dB above that obtained from LiNbO3 alone, and the convolution output is 24 dB above reports for LiNbO3 alone.
Effect of Relaxation on Small-Scale Filament Formation by Ultrashort Light Pulses
Authors: Fleck J. A. , Carman R. L.
Published: January 2004

The development of filamentary structure associated with the self-focusing of ultrashort pulses in the presence of dielectric relaxation is examined. Numerical solutions to the equations of self-focusing and relaxation display filament formation, although filament stabilization is strongly dependent on power. This suggests that further ingredients may be required for a complete theory of filament formation.
Analysis of CdTe as a γ-Ray Spectrometer
Authors: Zanio K. , Akutagawa W.
Published: January 2004

Gamma spectra were taken at room temperature with devices fabricated from semi-insulating CdTe. A resolution of 8 keV (FWHM) was found for 241Am (60 keV), 10 keV for 57Co (122 keV), 30 keV for 137Cs (662 keV), and 75 keV for 60Co (1.33 MeV). The photoelectric absorption coefficient at a photon energy of 122 keV was measured to be 5.4 ± 0.4 cm−1 in CdTe. The escape of the photoelectron at higher photon energies degraded the spectra and lowered the absorption coefficients below their theoretical values. Devices were also encapsulated within probes and their efficiency to photoelectric events was compared with that of a silicon detector. Ratios of 150:1 for 57Co and 12:1 for 241Am were found favoring CdTe.
Four-Hundredth-Order Harmonic Mixing of Microwave and Infrared Laser Radiation Using a Josephson Junction and a Maser
Authors: McDonald D. G. , Risley A. S. , Cupp J. D. , Evenson K. M. , Ashley J. R.
Published: January 2004

For mixing in a Josephson junction at infrared frequencies, we have shown that the available power from the junction increases as the intermediate frequency is increased. Following this result an infrared receiver has been developed incorporating a 9-GHz maser preamplifier at the i.f. Using this system, the beat between the 401st harmonic of a high-quality microwave source and a 3.8-THz infrared laser has been observed. Also, for low-order mixing at 3.8 THz, a comparison of beat signals from a Josephson junction and a room-temperature mixer has been made.
Nonresonant Energy Transfer from Er3+ to Yb3+ in LaF3
Authors: Okamoto Eichi , Masui Hiromitsu , Muto Katsutoshi , Awazu Kenzo
Published: January 2004

Energy transfer in LaF3; Er, Yb is studied by observing the lifetimes of Er3+ in excited states and the excitation spectra both at room temperature and at 77 °K. It is found that the energy transfer from Er3+ (4S3/2→4I13/2) to Yb3+ (2F7/2→2F5/2) is associated with the emission of three phonons of about 350 cm−1, and that the energy transfer from Er3+ (2H9/2→4F9/2) to Yb3+ accompanied by the absorption of phonons takes place.
Small-Signal Negative Conductance in BARITT Devices
Authors: EerNisse E. P.
Published: January 2004

Numerical calculations utilizing a realistic carrier velocity vs electric field relationship have been carried out for the dc current-voltage characteristics and small-signal ac response of abrupt Si p+np+, p+nvp+, n+pn+, and n+pπn+ barrier injection transit time (BARITT) devices. The small-signal ac response of these devices can be represented accurately by the depletion capacitance either in parallel with a negative conductance or in series with a negative resistance. The negative conductance has maximum amplitude for transit angles of approximately 1.55π and dc current density biases of 20–100 A/cm2. A distinct advantage was found in small-signal applications for p+np+ devices over p+nvp+ devices and for n+pn+ devices over n+pπn+ devices.
Glass-Forming Ability vs Local Order and Covalent Character in the As–Te System
Authors: Cornet J. , Rossier D.
Published: January 2004

An experimental study of the constitution of the As–Te glasses has been carried out, using glass-forming-ability measurements, high-angle diffraction, differential thermal analysis, and other thermodynamic determinations. Evidence is definitely given for a difference of valency between crystalline and glassy states. A model is suggested for the structural units in the glass and for the modifications induced by an excess of arsenic or tellurium with respect to the critical As2Te3 composition.
Higher-Order Distributed Feedback Oscillators
Authors: Bjorkholm J. E. , Shank C. V.
Published: January 2004

We report the observation of higher-order disftributed-feedback (DFB) laser oscillation using sinusoidal susceptibility modulation. For higher-order DFB oscillation the period of the susceptibility modulation is a multiple m of one-half the lasing wavelength. We have obtained tunable DFB oscillation for m=2 and m=3 by pumping rhodamine 6G with interference fringes. A discussion of two possible mechanisms which could account for our observations is presented. Higher-order DFB operation reduces the resolution required for fabricating a DFB laser.
Vibrational Population, Gain, and Excitation Mechanism of the Carbon Monoxide Laser
Authors: Lotkova E. N. , Mercer G. N. , Sobolev N. N.
Published: January 2004

The absolute vibrational population distribution of a cooled CO–He laser plasma has been measured and is in excellent agreement with theoretical predictions based on V-V anharmonic exchange relaxation, particularly when measured values of electron density are considered. The population distribution was obtained from small-signal-gain measurements at the line centers of 21 vibration-rotation transitions in a wavelength-selective laser oscillator.
Light Amplification in a Thin Film
Authors: Chang M. S. , Burlamacchi P. , Hu C. , Whinnery J. R.
Published: January 2004

Light amplification at 6328 Å in a rhodamine-B-doped polyurethane thin film is observed. The light-guiding thin film is pumped transversely with a nitrogen laser. Superradiant light of the dye-doped film is observed to be guided by the thin film. When a He–Ne light at 6328 Å is coupled into the same thin film along the same path, amplification results. Maximum unsaturated gain on the order of 13 cm−1 was experimentally determined by two different methods in a single-mode thin-film light guide with a concentration of 3.3×10−2 mol/liter when wet.
Effect of Hydrogen on CO2 TEA Lasers
Authors: Deutsch Thomas F.
Published: January 2004

The addition of several Torr hydrogen to a transversely excited pulsed high-pressure CO2 laser using continuous shaped electrodes has been found to suppress the formation of bright arcs and lead to better pulse-to-pulse reproducibility. The hydrogen increases the threshold energy for arc formation and leads to as much as a factor of 2 increase in the power output of the laser. The gain of the laser is also increased by the addition of hydrogen.
Increase of Dislocation Density in Ice by Dissolved Hydrogen Fluoride
Authors: Jones Stephen J. , Gilra Narendra K.
Published: January 2004

X-ray topography shows that at − 18°C small amounts of hydrogen fluoride diffused into ice single crystals increased the density of dislocations by a factor of about 5 by introducing both prismatic dislocation loops and additional b=〈112̄0〉 dislocations.
Formation of Injecting and Blocking Contacts on High-Resistivity Germanium
Authors: Ottaviani G. , Marrello V. , Mayer J. W. , Nicolet M-A. , Caywood J. M.
Published: January 2004

The behavior of Al and Sb/Ge/Sb layers evaporated on high-purity Ge and heat treated at 280 °C is studied by reverse-recovery, double-injection, and nuclear-particle-response techniques. The results indicate that the contacts have the injection and blocking characteristics of p- and n-type material, respectively. Backscattering measurements with 1.8-MeV 4He+ ions show that solid-solid reactions occur.
Solid-Phase Growth of Ge from Evaporated Al Layer
Authors: Caywood J. M. , Fern A. M. , McCaldin J. O. , Ottaviani G.
Published: January 2004

Solid Al was used as a medium from which to grow Ge onto a substrate of crystalline Ge. Evidence for growth was obtained from MeV He+ backscattering, which showed both Ge dissolution and growth can occur at the Ge/Al interface. Backscattering experiments also indicated transport from evaporated Ge through the Al medium to a crystalline Ge substrate. Diodes formed by temperature cycling a structure of n-type Ge/Al showed hole injection into the substrate during reverse-recovery-time measurements, confirming the expectation that Ge growth is present and is heavily p type from incorporation of the Al solvent during growth.
Time-of-Flight Mobility and Trapping Results for ZnSe
Authors: Heaton John L. , Hammond George H. , Goldner Ronald B.
Published: January 2004

Time-of-flight mobility and trapping results for zinc selenide are presented. The data were obtained at room temperature for electric fields in the range 3×104−8×105 V/cm. A relatively constant hole mobility (∼50 cm2/V sec) was found for the entire range of investigated fields. The electron mobility was approximately constant (∼400 cm2/V sec) up to E≃3×105 V/cm, above which the drift velocity remained constant. No obvious negative differential mobility was observed, even though the Gunn effect has been reported for the field range investigated. Trapping and detrapping times in the vicinity of 1 nsec are reported for both holes and electrons. The field dependence of the electron-trapping times is unusual and remains unexplained.
Structure on the High-Energy Side of the KL23M Auger Peak from Solid Aluminum: Internal Photoemission
Authors: Powell C. J.
Published: January 2004

Some weak structure on the high-energy side of the L23MM Auger peaks for Al and Si has been recently interpreted as being possibly due to the simultaneous decay of an inner-shell vacancy and a volume plasmon. It is shown here that similar structure due to multiple ionization is to be expected and that photoemission caused by internally generated x rays can be observed if the fluorescent yield is not too small. Relatively strong structure of the latter type has been observed in the secondary-electron energy distribution of evaporated Al on the high-energy side of the KL23M Auger peak.
Electrohydrodynamic Instabilities in Nematic Liquid Crystals in Low-Frequency Fields
Authors: Meyerhofer Dietrich , Sussman Alan
Published: January 2004

The threshold for domain formation and the characteristics of domains have been measured over an extended frequency range. Comparison with the Helfrich-Orsay theory shows a good fit of the threshold over a wider than expected variation of cell thicknesses. This is even true near the ``critical'' frequency where the domain size decreases with increasing frequency. In addition, a new domain regime is described at frequencies smaller than the inverse ion transit time.
Instantaneous Turbulence Velocity Measurement by Laser Doppler Velocimeter
Authors: Wang C. P.
Published: January 2004

A frequency-modulation (FM) demodulation scheme for the measurement of instantaneous velocity of turbulent flow by laser Doppler velocimeter is proposed. An analysis based on the theory of optical-mixing spectroscopy is given.
CO Laser Line Selection for High Atmospheric Transmission
Authors: Bhaumik M. L.
Published: January 2004

An intracavity gas-cell technique is demonstrated for restricting the carbon monoxide (CO) laser oscillations to lines coincident with the transmission bands of the atmosphere. Using an intracavity water-vapor cell, the CO laser gain was spoiled in lines that are highly absorbed by the atmospheric water vapor, permitting the oscillations to build up only on the higher transmission lines.
Very-Low-Current Operation of Mesa-Stripe-Geometry Double-Heterostructure Injection Lasers
Authors: Tsukada T. , Nakashima H. , Umeda J. , Nakamura S. , Chinone N. , Ito R. , Nakada O.
Published: January 2004

Mesa-stripe-geometry double-heterostructure lasers which operate at low-current level have been fabricated. Lasers of this geometry are made by etching the heterostructure layers, leaving a stripe region with a width ranging from 10 to 40 μm. The current-spreading effect inherent in stripe-geometry lasers is eliminated in this structure. As a result of the small active region and the low-threshold current density, a significant reduction of total threshold current has been realized. The lowest-threshold current is 50 mA in pulsed operation, and 75 mA in dc. The thermal resistance of the diode of this structure is nearly as low as that of the stripe-geometry laser.
Implanted Interstitial Boron Atoms in Silicon
Authors: Nétange B. , Cherki M. , Baruch P.
Published: January 2004

Photoconductivity methods are used to investigate high-resistivity n-type and p-type silicon implanted with doses of ∼1014 B+/cm2 of 100 keV. Besides the photoconductivity band associated with the divacancy, a photoconductivity level at ∼0.4 eV is detected in the spectrum. This level anneals at ∼300°C; it has been associated with boron interstitial atoms in sites of trigonal symmetry for boron-doped silicon irradiated with electrons. The appearance of this level is not so clear in the case of the p-type silicon substrate where the substrate contribution to the photoconductivity is larger.
Generation of Single Picosecond and Subpicosecond Light Pulses
Authors: Penzkofer A. , von der Linde D. , Laubereau A. , Kaiser W.
Published: January 2004

Picosecond light pulses passing through a saturable absorber show considerable pulse shortening. For instance, under special favorable conditions the pulse duration was found to be reduced from 8 to 2. 6 psec in a single transit. Using a multiple-absorber-amplifier system, light pulses were shortened from 8 to 0.7 psec in five transits. The shortest pulse seen in our experiments had a duration of less than 0.5 psec. Calculations based on a two-level approximation of the absorbing medium agreed well with the experimental results.
Light Scattering from High-Lying Electronic Excitations in CoF2
Authors: Hoff J. T. , Grunberg P. A. , Koningstein J. A.
Published: January 2004

Raman spectra of CoF2 above and below its Néel point have been obtained which show four very weak lines in the region between 700 and 1500 cm−1. These are attributed to transitions from the ground state to the four highest-lying levels within the resolved Γ4+4 manifold of Co2+. The spectra are in good agreement with data for Co2+ in MgF2.
Rayleigh-Wave Electromechanical Coupling Constants
Authors: Schulz M. B. , Matsinger J. H.
Published: January 2004

The relative change in surface-acoustic-wave velocity, Δν/ν∞, caused by a thin conducting film on the surface, has been measured for several orientations of LiNbO3, quartz, LiTaO3, Bi12GeO20, and ZnO. This measurement was accomplished by monitoring the phase shift of surface-wave delay lines as an aluminum film was vacuum deposited onto the propagation path. Less than 100-Å-thick films completely short circuited the surface electric field. From the results, new more accurate values of surface-wave coupling constants are derived.
Photoconductivity of CdS crystals irradiated with fast electrons
Authors: Yoshida Toshio , Oka Takashi , Kitagawa Michiharu
Published: January 2004

The effects of 10-MeV electron irradiation on the photoconductivity of CdS single crystals were studied. Irradiation causes the appearance or increase of photoconductivity in the wavelength ranges from 0.8 to 3 μ (the 1-μ band), from 0.55 to 0.8 μ, and from 0.46 to 0.5 μ (the exciton band). The 1-μ band is attributed to radiation-produced defects located at levels from 0.4 to 1.6 eV below the bottom of the conduction band. The excitonic band results from dissociation of excitons at some kinds of radiation-produced defects.
Alpha- and proton-induced x-ray deexcitation of titanium
Authors: Richard Patrick , Senglaub Mike , Johnson Brant , Moore C. Fred
Published: January 2004

Measurements of Kα and Kβ x rays induced by proton and α-particle beams from an electrostatic accelerator show a divergence from the normal x-ray spectra as the nuclear charge increases. These measurements are consistent with the explanation that the ion excitation produces multiple inner-shell electron vacancies, which in turn cause electronic-shell energy shifts. The intensity of these shifted lines is a measure of the amount of multiple inner-shell ionization.
Isotope separation rate in Haeffner effect
Authors: Sinha Om P.
Published: January 2004

A simple theory is presented for Haeffner effect based on the ideas of Fiks. An exact formula derived for the isotope separation rate appears to be in good agreement with the experimental data on several systems.
Boron atom distributions in ion-implanted silicon by the (n,4He) nuclear reaction
Authors: Ziegler J.F. , Crowder B.L. , Cole G.W. , Baglin J.E.E. , Masters B.J.
Published: January 2004

The concentration distribution of 10B atoms ion-implanted into silicon has been determined with a new nuclear reaction technique, The concentration profiles for implantations in the energy range 40–500 keV were determined before and after annealing at 900 °C for 30 min and show that enhanced diffusion, because of radiation damage, is of minor importance. The profile ranges and widths have been compared to LSS theory and to other experiments.
Excitation of a long-pulse CO2 laser with a short-pulse longitudinal electron beam
Authors: Marcus S.
Published: January 2004

A 3-nsec pulse of 600-keV electrons has been used to ionize a CO2–N2–He medium from which laser pulses lasting up to 120 μsec have been obtained. The electron beam is nearly collinear with the laser axis and normal to the sustainer field. Pulse energies of 11.5 J have been obtained from the 75-cm-long device.
On the nature of the kink in the carrier profile for phosphorus-diffused layers in silicon
Authors: Schwettmann F.N. , Kendall D.L.
Published: January 2004

The mechanism of formation of the kink in the impurity profile of phosphorus-diffused layers in silicon is shown to be related to the ``tail'' that is formed during low-temperature heat treatments. The concentration at which the tail is formed is a function of temperature with an activation energy of 0.79 eV. The enhanced diffusion which gives rise to the tail depends on processes occurring in the high-concentration region. A complex model is required to explain all of these results.
Picosecond holography
Authors: Fourney M.E. , Barker D.B.
Published: January 2004

A simple off-axis hologram has been recorded on thin bismuth film using a train of picosecond pulses from a mode-locked Nd: glass laser. Due to the ultrashort pulse duration and temporal coherence length of the laser, a time-of-arrival principle is utilized to show the correspondence of a point on the hologram to some specific region of the object.
Spectral analysis of backscattered light from laser-produced plasma: reexamined
Authors: Belland P. , DeMichelis C. , Mattioli M. , Papoular R.
Published: January 2004

Previous measurements on the backscattered light from a laser-produced plasma, showing a line structure, have been incorrectly interpreted. New experiments reveal a shift of the backscattered light together with considerable broadening.
Backscattering investigation of low-temperature migration of chromium through gold films
Authors: Hirvonen J.K. , Weisenberger W.H. , Westmoreland J.E. , Meussner R.A.
Published: January 2004

Backscattering of 3.0-MeV 4He ions has been used to investigate the low-temperature migration of Cr into and through thin Au films (1000 and 2000 Å) deposited by evaporation and sputtering. Significant Cr migration is seen at annealing temperatures of 250 and 450 °C for periods of 0.5–22 h, whereas no migration of Cr in the Au was detected in any of the as-deposited samples or after a 150 °C 0.5-h anneal.
Laser-induced damage in transparent dielectrics: ion beam polishing as a means of increasing surface damage thresholds
Authors: Giuliano Concetto R.
Published: January 2004

Polishing of sapphire surfaces with energetic Ar+ ion beams is shown to result in a substantial increase in laser damage threshold over that for conventionally polished surfaces. Data for both entrance and exit damage are presented. The results are interpreted in terms of an increase in surface strength with ion beam polishing.
Injection luminescence and laser action in epitaxial PbTe diodes
Authors: Holloway H. , Weber W.H. , Logothetis E.M. , Varga A.J. , Yeung K.F.
Published: January 2004

Thin-film diode lasers have been made from Schottky barriers on epitaxial PbTe. At 77 °K the spontaneous emission spectrum agrees with that calculated for direct band-to-band transitions. At 12 °K laser action is observed in the pulsed mode with an average current density, at threshold, of (2–3) × 102 A cm−2. This is the first observation of diode laser action from evaporated thin films of any semiconductor.
Measurement of magnetic bubble mobility in epitaxial garnet films
Authors: Vella-Coleiro G.P. , Tabor W.J.
Published: January 2004

A technique for measuring the velocity of a circular magnetic domain in a magnetic field gradient is described. The method has been applied to epitaxial garnet films, and results are presented for a film of nominal composition Eu1Er2Ga0.7Fe4.3O12. The technique is compared with other methods of measuring domain wall mobility.
Parametric study of the optical storage effect in mixed liquid-crystal systems
Authors: Hulin J.P.
Published: January 2004

The lifetime τ of the storage effect in mixtures of cholesteric and nematic liquid crystals is found to depend exponentially on the L/P (thickness/pitch) ratio. τ can be changed from 1 min to several days by varying L/P from 2 to 15.
Performance characteristics of a helical TEA CO2 laser
Authors: Rampton D.T. , Gandhi O.P.
Published: January 2004

Cavity misalignment of a helical TEA CO2 laser, due to thermal bending of the beam, as well as thermal focusing effects has been observed. The spectral distribution of the energy is found to be invariant with gas mixtures, and the optimum N2 : CO2 ratio for peak power output is shown to be 1 : 1, with the addition of He being of no apparent value.
Magnetically controlled negative resistance and coherent oscillations in InSb
Authors: Kamakura Katutoshi , Shimizu Tukasa
Published: January 2004

Current-controlled negative resistance is observed in n-InSb in the impact-ionization region under nearly parallel electric and magnetic fields at 77 K. Furthermore, coherent low-frequency oscillations associated with negative resistance are observed by means of an external resonance circuit. Frequencies of coherent oscillations (5–22 MHz) depend strongly on the external circuit but are independent of the magnetic field intensity.
Laser-induced stress-wave and impulse augmentation
Authors: O'Keefe J.D. , Skeen C.H.
Published: January 2004

A series of experiments were performed on aluminum targets in order to find simple methods of increasing the stress and impulse using a laser. It was found by coating the aluminum targets with thin layers of transparent relatively volatile materials that order-of-magnitude increases were obtained over irradiating bare targets. Stress-wave amplitudes of 7.9 kbar were measured.
Laser oscillation and anisotropic gain in the 1 → 0 vibrational band of optically pumped HF gas
Authors: Skribanowitz N. , Herman I.P. , Feld M.S.
Published: January 2004

P-branch laser oscillations have been observed in the v = 1 → v = 0 band of HF gas, optically pumped by R-branch lines of a pulsed HF laser. The observed gains are large (> 10% cm−1) and the conversion efficiencies are high. In a ring cavity the system shows directional gain anisotropy characteristic of unidirectional laser amplifiers proposed recently.
Analysis of rf-sputtering glow discharge by spectroscopic method
Authors: Ratinen H.
Published: January 2004

The use of a spectroscopic method for analysing an rf-sputtering glow discharge is described. Both pure CaO disks and ones doped with Sm and Tm were used as targets, and the purpose of the sputtering was to prepare luminescence films. The sputtering was carried out in atmospheres of Ar, O2, N2, and Ne. The intensity of the strongest peak of calcium was measured in these discharges as a function of the distance from the target and of the rf voltage used. It was observed that impurities, in this case H and N2, were revealed, and a regular calcium flux from the target to the substrate could be well controlled by this method.
Theory of interference patterns in orthoferrites
Authors: Dmitrevsky S. , Desrosiers R.J.
Published: January 2004

A stripe pattern observed in orthoferrites illuminated at oblique incidence, previously explained using a ``virtual grating'' effect is reinterpreted as an interference pattern of two waves created at the domain boundary. The theory is extended to include the decrease in stripe spacing as the wall orientation is changed.
Laser dynamics and wavelength tuning in electron-beam-pumped GaAs
Authors: Kawasaki B.S. , Garside B.K. , Shewchun J.
Published: January 2004

A novel source of time-varying losses in electron-beam-pumped GaAs lasers is described. Over the range of electron-beam voltages typically employed in such lasers, this loss initially greatly exceeds that due to reflectivity losses at the cavity end faces. This loss is predicted to fall off rather dramatically as a function of time after the start of the pumping pulse. Such a dynamic loss has a number of consequences. In particular, it leads to a source of faster-than-band-gap wavelength tuning of the laser emission through an effect somewhat akin to the inverse of a dynamic Burstein shift.
Gettering rates of various fast-diffusing metal impurities at ion-damaged layers on silicon
Authors: Buck T.M. , Pickar K.A. , Poate J.M. , Hsieh C-M.
Published: January 2004

High-temperature gettering of Fe, Co, Ni, Cu, and Au by ion-damaged surface layers on silicon wafers has been studied by Rutherford backscattering of 4He+ ions incident at 1.75 or 2 MeV. Analysis showed impurity levels in the damaged layers ranging from 1013–1017/cm2. The metals fall into two groups: those which are gettered slowly-Fe, Co, and Au— and those gettered rapidly-Cu and Ni. This trend is predicted by a simple diffusion model using published interstitial solubilities and diffusivities.
Morphological asymmetry in laser damage of transparent dielectric surfaces
Authors: Boling N.L. , Dubé G. , Crisp M.D.
Published: January 2004

The morphological difference between entrance and exit surface damage is examined in terms of Fresnel reflections at the interface of the dielectric and the plasma associated with damage. It is suggested that the standing wave formed at the exit surface by the incident wave and the wave reflected from the plasma-dielectric interface is responsible for the characteristic pits of exit surface damage, while entrance damage characteristics are due to thermal shock from the hot plasma contiguous to the surface.
Cold-cathode electron-beam-controlled CO2 laser amplifier
Authors: Ahlstrom H.G. , Inglesakis G. , Holzrichter J.F. , Kan T. , Jenson J. , Kolb A.C.
Published: January 2004

A large-area—cold-cathode (10 × 100 cm) electron gun has been constructed and used to control of CO2 laser amplifier. Energy deposition of 226 J/liter in a time of 1 μsec has led to a gain of 4.9% cm in an atmospheric-pressure CO2 laser mixture.
Thin-film distributed-feedback laser fabricated by ion milling
Authors: Schinke D.P. , Smith R.G. , Spencer E.G. , Galvin M.F.
Published: January 2004

Distributed feedback of a thin-film optical guided mode has been produced by a periodic perturbation of the guide height. Using photoresist and ion-milling techniques, gratings with a period of ∼0.2 μ and a peak-to-peak height of ∼0.1 μ have been formed on fused silica substrates. A film of polyurethane doped with Rhodamine 6G pumped by an N2 laser formed the gain medium. Data presented on the oscillation threshold of several lasers are in agreement with calculated feedback parameters. This technique is capable of producing high-resolution gratings in durable materials which can provide feedback in low-gain laser media.
Pyroelectric copying process
Authors: Bergman J.G. , Crane G.R. , Ballman A.A. , O'Bryan H.M.
Published: January 2004

An electrostatic copying process based on the pyroelectric effect is described. The effect is demonstrated with single crystals of LiTaO3, ceramic plates of lanthanum-modified lead zirconate-titanate (PLZT), and polymer films of polyvinylidene fluoride (PVF2). By employing thin films (0.8 mil) of PVF2 to minimize thermal diffusion, we have obtained sufficient resolution to allow charge distributions (images) to be visually observed by dusting the films with conventional electrostatically charged inks. Since the pyroelectric effect is not wavelength dependent, certain advantages over photoconductive techniques, with their inherent wavelength dependence, are possible.
Auger electron spectroscopy and sputter etching of Ni/Au–Ge on n-GaAs
Authors: Robinson G.Y. , Jarvis N.L.
Published: January 2004

A new diagnostic technique was used to examine the alloying behavior of the Ni/Au–Ge Ohmic contact to n-type GaAs. By combining Auger electron spectroscopy with sputter etching, depth-composition profiles of Ni, Au, Ge, Ga, and As were obtained for alloyed and unalloyed samples. Gallium out-diffusion and surface accumulation during alloying was observed. The degree of Ga out-diffusion as well as the redistribution of Ga and As in the alloyed region was found to depend on the orientation of the GaAs substrate. It was shown that the overlaying Ni film does not cover the Au–Ge uniformly during alloying.
Optical measurement of the ion temperature in a barium Q plasma
Authors: Gekelman W. , Hart T.R. , Rogers K.C. , Motz R.O.
Published: January 2004

The ion temperature in a single-ended barium Q machine has been determined optically, with and without current drawn through the machine. Ion temperatures which were consistent or slightly higher than the hot-plate temperature of 0.25 eV rose to 5–7 eV when an electron drift was initiated. The ion temperature rose to 1 eV if an ion current was drawn along the column. These phenomena are independent of magnetic field.
Subnanosecond pyroelectric detector
Authors: Roundy C.B. , Byer R.L.
Published: January 2004

We have designed and tested a 500-psec-rise-time pyroelectric detector. The responsivity is great enough to drive a Tektronix 519 oscilloscope when amplified with a 1.0-GHz-bandwidth amplifier. To obtain broad spectral response we have developed a thermally fast-absorbing black which has approximately 50% absorption from 0.3 μ to greater than 50 μ, and transfers 90% of the absorbed energy to the pyroelectric crystal in 400 psec. The maximum detector output voltage prior to amplification is 2. 0 V, limited by the absorbing black's burn intensity.
Influence of the current-phase relationship on the I-V characteristic of superconducting weak links
Authors: Auracher F. , Van Duzer T.
Published: January 2004

I-V characteristics with and without hysteresis are calculated for various current-phase relations. We show that the shape of the current-phase relation has a significant influence on the shape of the I-V characteristic and the amount of hysteresis in it.
Subharmonic generation of surface and bulk acoustic waves at high pump amplitudes in piezoelectric semiconductors
Authors: Zemon S. , Conwell E.
Published: January 2004

Parametric amplification of acoustic noise has been studied for high-amplitude surface and bulk waves in photoconducting CdS. In contrast to the situation at low amplitudes, the amplified noise is collinear with the pumping wave and is contained in an extremely narrow band around one-half the pump frequency. These results, as well as the observed voltage and time dependence, can be accounted for by the tight carrier bunching that occurs at high wave amplitudes.
Emission spectra of Cd1−xMgxTe light-emitting diodes
Authors: Shitaya Takao , Ishida Toru , Sato Hisanao
Published: January 2004

Visible light-emitting diodes have been fabricated from Cd1−xMgxTe (x ≈ 0.43). An external quantum efficiency of 2×10−4 has been obtained at room temperature. Emission spectra of the diodes consist of two broad bands peaking at 640 and 700 mμ, relative intensities of which depend on the concentration of Al doped as donors. The photoluminescence measurements indicate that the 640-mμ band is produced by a combination of doping P as an acceptor and heating in Cd vapor. The 700-mμ band is enhanced by Al and is attributable to lattice defects induced by Al doping.