jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue

15 Dec 1992

Volume 72, Issue 12, pp. 5535-6019

Page 1 of 3 Pages Next Page | Jump to Page

Temperature dependence of the ruby luminescence method for measuring high pressures

J. Yen and M. Nicol

J. Appl. Phys. 72, 5535 (1992); http://dx.doi.org/10.1063/1.351950 (4 pages) | Cited 26 times

Full Text: | Download PDF

Show Abstract
Pressures in diamond‐anvil high‐pressure cells often are determined by measuring ruby emission spectra because the R1 luminescence has high quantum efficiency and frequency of the R1 band shifts almost linearly with pressure, independent of temperature. To more than 600 K, pressures can be precisely determined by measuring luminescence spectra at ambient and high pressures at the same temperature. The temperature dependence of the frequency of the R1 line is not simple, and empirical approximations have been developed so that a pressure at a known temperature might be estimated from measurements of spectra at that P and T and at ambient pressure and one temperature; that is, without measuring the R1 line at ambient pressure at each temperature. Measurements reported here show that, between 100 and 260 K, pressures computed by using empirical approximations calibrated near ambient temperature may be in error from 0.1 to several GPa. The temperature dependence of the R1 line is accurately described by the function suggested by McCumber and Sturge [J. Appl. Phys. 34, 1682 (1963)]. Measurements at several temperatures between 100 and at least 400 K are needed to evaluate the precise parameters of this function appropriate for a particular spectrometer and ruby. Therefore, it is often practical for studies at pressures to a few GPa simply to determine the wavelength of the R1 line at a given temperature and ambient pressure by measuring it.
Show PACS
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
78.55.Hx Other solid inorganic materials

Calibration of the ruby R1 and R2 fluorescence shifts as a function of temperature from 0 to 600 K

Deirdre D. Ragan, R. Gustavsen, and David Schiferl

J. Appl. Phys. 72, 5539 (1992); http://dx.doi.org/10.1063/1.351951 (6 pages) | Cited 69 times

Full Text: | Download PDF

Show Abstract
Recent work by Gupta and Shen [Appl. Phys Lett. 58, 583 (1991)] has shown that in a nonhydrostatic environment, the frequency of the ruby R2 line provides a reliable measure of the mean stress or pressure. When using the frequency of either the R1 or R2 line to measure pressure at nonambient temperature, it is necessary to know the temperature dependence of the line shift. Unfortunately, the shift of the R2 line with temperature has not been reported. The ruby R1 and R2 fluorescence shifts have been determined as a function of temperature from 15 to 600 K. Both can be fitted very well to the simple cubic forms R1(T) =14 423+4.49×10−2T−4.81×10−4T2+3.71×10−7T3 cm−1 and R2(T)=14 452 +3.00×10−2T−3.88×10−4T2+2.55×10−7T3 cm−1. From 300 to 600 K the shifts fit well to linear functions of temperature. In addition, it is found that the R1‐R2 splitting changes by about 3 cm−1 over the 600 K temperature range. Linewidths were found to vary both with temperature and from sample to sample.
Show PACS
07.35.+k High-pressure apparatus; shock tubes; diamond anvil cells
78.55.Hx Other solid inorganic materials

Characteristics of discharge‐excited barium vapor lasers operating in the 1–5 μm spectral band

H. M. Pask and J. A. Piper

J. Appl. Phys. 72, 5545 (1992); http://dx.doi.org/10.1063/1.351952 (10 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
Laser action from barium vapor has been investigated using small‐scale (20–40 cm−3) high‐repetition‐rate discharge‐heated and low‐repetition‐rate externally‐heated devices. Strongest output occurs at 1.13, 1.50, and 2.55 μm, with weaker emission at 2.92 and 4.72 μm. The range of discharge conditions for which laser action occurs at these wavelengths is described and the temporal occurrence of laser output is presented. The implications of this study to the future development of barium lasers are considered.
Show PACS
42.55.Lt Gas lasers including excimer and metal-vapor lasers
42.60.By Design of specific laser systems
52.80.Hc Glow; corona

Light power dependence of electro‐optical transmission in InGaAs/AlGaAs multiple quantum wells

Stephen Giugni, Kenji Kawashima, Naokatsu Sano, and Kenzo Fujiwara

J. Appl. Phys. 72, 5555 (1992); http://dx.doi.org/10.1063/1.351953 (6 pages)

Full Text: | Download PDF

Show Abstract
Dual wavelength electro‐optical bistability in resistor‐biased and symmetric self electro‐optic effect devices and their input power dependence are investigated using InGaAs/AlGaAs multiple quantum wells. A new principle to drive the devices using two widely separated wavelengths for signal and control light is proposed and demonstrated to obtain optical transmission bistability between two stable states of the signal light at λ1 by varying the control beam power at λ2. Detailed experimental results of signal power dependencies of the optical responses are presented and rigorously explained based on the voltage switching mechanism of the signal diode by the second control light using a simple load line analysis. Advantages of this new device configuration are discussed taking full merit of the transparency of the GaAs substrate to the signal wavelength.
Show PACS
42.65.Pc Optical bistability, multistability, and switching, including local field effects
78.20.Jq Electro-optical effects
42.79.Sz Optical communication systems, multiplexers, and demultiplexers

High transfer‐efficiency microsurface acoustic wave directional couplers

I. Haruvi‐Busnach, M. Zilberstein, G. Golan, A. Seidman, and N. Croitoru

J. Appl. Phys. 72, 5561 (1992); http://dx.doi.org/10.1063/1.351954 (4 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
Surface acoustic waves (SAWS) directional couplers have long been known in both microwave and integrated acoustic applications. Such couplers, when both channels are of different widths and different dispersion characteristics, may also be used as electronic filters. SAW directional couplers are ideal for inclusion in acoustical signal processing devices, as modulators or switches. This article represents formulation and physical properties of advanced high transfer efficiency SAW directional couplers, using the coupled mode theory. One kind of directional coupler is especially considered and discussed in detail. The obtained coupling parameters are applicable to any guided modes in parallel waveguides of the same cross section, similar to 1/v index of refractive and identical shapes. Coupling constants and physical parameters for the coupled acoustic modes, computed according to this theory, are shown and seem to agree very well with experimental data.
Show PACS
43.60.+d Acoustic signal processing
72.50.+b Acoustoelectric effects

Frequency dependence of ultrasonic velocity and attenuation in two‐phase composite systems with spherical scatterers

Ingo Alig and Dirk Lellinger

J. Appl. Phys. 72, 5565 (1992); http://dx.doi.org/10.1063/1.351955 (6 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
The frequency dependence of the scattering contribution of ultrasonic attenuation and sound velocity of longitudinal waves was measured in a frequency range from 2 to 50 MHz. For model systems we used gelatine samples with 20 wt % glass beads of 315–400 μm and 180–250 μm diameter and with 10 wt % glass beads of 42–174 μm diameter. The application of a recently developed Fourier transform technique allowed us to observe both ultrasonic attenuation and velocity with sufficiently high accuracy for quantitative comparison with sound scattering theory. The frequency dependence of sound attenuation shows multiple maxima, whereas in the frequency dependence of the velocity difference a sharp minimum on the order of 1% of the absolute velocity occurs. For the simulation of ultrasonic attenuation and sound velocity we combined a multiple scattering approach from Waterman and Truell [J. Math. Phys. 2, 512 (1961)] with a acoustic resonance scattering theory for a viscoelastic sphere developed by Ayres and Gaunaurd [J. Acoust. Soc. Am. 81, 301 (1986)]. Supplementary in the computations, the attenuation of the matrix and the particle size distribution were taken into account. Comparison of the simulated data to the experimental results shows good agreement.
Show PACS
43.35.-c Ultrasonics, quantum acoustics, and physical effects of sound
62.80.+f Ultrasonic relaxation
81.05.Rm Porous materials; granular materials
81.70.-q Methods of materials testing and analysis

Variational theory of the radiant emittance of the mercury argon discharge and the effects of isotopic enrichment

R. W. Richardson and S. M. Berman

J. Appl. Phys. 72, 5571 (1992); http://dx.doi.org/10.1063/1.351956 (8 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
A variational theory of the radiant emittance of the mercury‐argon discharge is developed and applied to an investigation of the effects of alterations of the isotopic composition of the mercury. The theory includes the effects of transport of resonance radiation, elastic and inelastic collisions, resonant exchange of excitation, diffusion of the mercury atoms, the isotope‐ and hyperfine‐shifted structure of the resonance line, and the surfaces of the discharge on the emittance. Two sensitive parameters—the branching ratio for radiative decay of the resonance state and the rate constant for resonant exchange of excitation—are fitted to data on natural mercury. The remaining insensitive parameters are given values based on microscopic estimates. The resulting theory reproduces the experimentally observed results for mercury—196 enhanced mixtures. We predict small effects for mixtures with other isotopes enhanced. The crucial role played by resonant exchange of excitation is emphasized.  
Show PACS
52.80.Hc Glow; corona
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.80.-s Electric discharges

Modeling and measurements of the negative ion flux from amplitude modulated rf discharges

Lawrence J. Overzet, Yun Lin, and Laizhong Luo

J. Appl. Phys. 72, 5579 (1992); http://dx.doi.org/10.1063/1.351957 (14 pages) | Cited 35 times

Full Text: | Download PDF

Show Abstract
The time dependent as well as amplitude modulation frequency dependent ion flux from parallel plate radio frequency discharges have been measured by mass spectrometry and modeled using the fluid equations. The negative ion flux to the grounded electrode becomes large after the rf excitation is turned off and has complex temporal features which depend upon the ion, gas mixture, applied dc bias voltage and other externally controlled parameters. Some of these features can be explained with the assistance of the fluid equation model. In short, negative ions can be formed during the active glow as well as after the glow excitation has been turned off. The resulting negative ion flux to the grounded electrode during the afterglow is determined in part by when the negative ion is formed. For example, if the amplitude modulation frequency at which the flux of a negative ion goes to zero is larger than 100 kHz, it indicates that ion is formed in the afterglow. (Of course, it may exist during the active glow as well.) Conversely, ions with signal only at small modulation frequencies are unlikely to have been produced by attachment in the afterglow. The experimental results are from CF4 and Cl2‐He discharges. One finding was that the temporal and modulation frequency dependencies of F− and SiF5− ions from CF4 discharges indicate that SiF5− exists only in a thin layer above the grounded electrode.
Show PACS
52.80.Hc Glow; corona
52.70.Nc Particle measurements
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)

Ion irradiation damage in n‐type GaAs in comparison with its electron irradiation damage

F. H. Eisen, K. Bachem, E. Klausman, K. Koehler, and R. Haddad

J. Appl. Phys. 72, 5593 (1992); http://dx.doi.org/10.1063/1.351958 (9 pages) | Cited 24 times

Full Text: | Download PDF

Show Abstract
In an effort to attain a better understanding of the nature of the defects introduced in GaAs by irradiating it with energetic light ions; electron or proton irradiated n‐type GaAs samples, cut from the same layer grown by molecular‐beam epitaxy, have been studied by deep level transient spectroscopy. By comparing the spectra, including the effects of high electric fields, and by using results for annealed samples, it is possible to determine which of the traps reported in electron irradiated GaAs, most of which are believed to be arsenic interstitial‐vacancy pairs, are present in the proton irradiated material. The traps identified in proton irradiated GaAs include most of those found in electron irradiated material, either after irradiation or after irradiation and annealing. The results indicate that two of these traps are associated with defects which are more complex than simple interstitial‐vacancy pairs. Two traps were found in proton irradiated material which have not been observed in electron irradiated GaAs. One of these is nearly as abundant as the prominent E3 center observed in electron irradiated GaAs and is probably also not a simple pair. The deep level transient spectroscopy peak for this trap is not clearly separated from that of E3 in proton irradiated GaAs. The other trap is probably associated with a particular impurity present in the MBE grown sample layers.
Show PACS
61.80.Jh Ion radiation effects
71.55.Eq III-V semiconductors

Ion mixing enhanced wafer bonding for silicon‐on‐insulator structures

N. Q. Khánh, M. Fried, A. Tóth, J. Gyulai, and B. Pécz

J. Appl. Phys. 72, 5602 (1992); http://dx.doi.org/10.1063/1.351959 (4 pages)

Full Text: | Download PDF

Show Abstract
Bonding of a 1360‐nm‐thick single crystalline silicon membrane onto an oxidized wafer was enhanced by ion mixing using 1250 keV 14N+ ion implantation. The oxidized wafer was covered by a thin, thermally grown oxide (134 nm) and implantation was performed either in random or in channeling directions through the membrane. Ion doses were in the range of 0.5×1016 to 5×1016 atoms/cm2. Implantation was followed by an annealing at 1000 °C for 0.5 h in nitrogen gas to remove the radiation defects. Due to the effect of implantation, the bonding quality was very good in all cases. In addition, results of Rutherford backscattering spectroscopy and transmission electron microscopy showed that using channeled implantation with a dose of 0.5×1016 atoms/cm2, the adherent silicon layer was of high quality (∼1.5×103 dislocations/cm2) and the interface remained sharp.
Show PACS
61.72.uf Ge and Si
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.35.Fx Diffusion; interface formation

Thermoelastic behavior of grain‐boundary superlattices

S. R. Phillpot

J. Appl. Phys. 72, 5606 (1992); http://dx.doi.org/10.1063/1.351960 (10 pages) | Cited 2 times

Full Text: | Download PDF

Show Abstract
The thermal‐expansion coefficients of superlattices of twist grain boundaries on the (100) plane in fcc Cu and Au are calculated using a generalization of the Grüneisen relation. A strong anisotropy in the in‐plane and out‐of‐plane thermal‐expansion coefficients is found. The thermal expansion of these superlattices is found to be determined from a complex interplay of the structural disorder arising from the interfaces with the associated zero‐temperature lattice‐parameter changes. The relationship between the thermal expansion and the elastic properties is explored.
Show PACS
61.72.Mm Grain and twin boundaries
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
65.40.De Thermal expansion; thermomechanical effects

Generation of divacancies in silicon by MeV electrons: Dose rate dependence and influence of Sn and P

Bengt G. Svensson and J. Lennart Lindström

J. Appl. Phys. 72, 5616 (1992); http://dx.doi.org/10.1063/1.351961 (6 pages) | Cited 23 times

Full Text: | Download PDF

Show Abstract
Silicon samples doped with tin and/or phosphorus have been irradiated at room temperature by 2.0 MeV electrons in order to study the generation of divacancy centers (V2). The samples were analyzed using low‐temperature infrared absorption measurements and deep level transient spectroscopy. The production of V2 is found to be very small in the tin‐doped samples, which suggests that the generation process hinges strongly on the existence of mobile monovacancies. Substitutional Sn atoms act as efficient traps for migrating vacancies and form stable vacancy‐tin centers with a corresponding reduction in the formation of ‘‘ordinary’’ vacancy‐related defects. Indeed, at temperatures above ∼150 °C where the vacancy‐tin centers dissociate, a pronounced increase in the V2 concentration occurs. On the other hand, measurements of the V2 concentration in the non tin‐doped samples as a function of electron dose using different dose rates reveal that the steady‐state concentration of monovacancies during irradiation has no influence on the generation of V2. Thus, pairing of two single vacancies created by different bombarding electrons can be excluded as a major formation mechanism for V2. Evidence is presented for a new model where the formation of V2 is predominantly due to migration and subsequent agglomeration of two single vacancies created directly (electron‐atom collision) and indirectly (recoiling atom‐atom collision), respectively, by the same impinging electron. Finally, the presence of substitutional phosphorus atoms in high‐purity float zone Si samples is shown to enhance the production of V2. The experimental data exhibit excellent relative agreement with computer simulations assuming a defect reaction model where annihilation of vacancy‐phosphorus centers by Si self‐interstitials is taken into account, i.e., the role of phosphorus is to provide an alternative recombination center for the Si self‐interstitials with a corresponding growth of surviving V2 centers.
Show PACS
61.80.Fe Electron and positron radiation effects
61.72.jd Vacancies
61.72.jj Interstitials
71.55.Ht Other nonmetals
78.30.-j Infrared and Raman spectra
78.40.Fy Semiconductors

Role of impurities on diffusion‐induced defective states

A. Castaldini, A. Cavallini, B. Fraboni, and E. Giannotte

J. Appl. Phys. 72, 5622 (1992); http://dx.doi.org/10.1063/1.351962 (6 pages)

Full Text: | Download PDF

Show Abstract
The defective states induced in floating zone Si by the heavy diffusion of dopants have been investigated by means of the electron beam‐induced current method. By measuring the minority carrier diffusion length with the first order moment method, and by directly imaging the defects, their electrical activity has been analyzed. The diffused samples have subsequently been dry oxidized, so that the evolution of the electrical and morphological properties of the induced defects could be followed. Two sets of samples, one diffused with B and the other with B and Al, have been investigated in order to study the effects of the presence of Al. Significant improvements in the diffusion length have been observed in samples where Al had been codiffused, thus providing indication for the role played by Al on the electrical activity of bulk defective states.
Show PACS
61.72.Yx Interaction between different crystal defects; gettering effect
66.30.J- Diffusion of impurities
72.80.Cw Elemental semiconductors

Acoustic quality factor of molybdenum and tungsten at low temperatures

William Duffy

J. Appl. Phys. 72, 5628 (1992); http://dx.doi.org/10.1063/1.352324 (7 pages) | Cited 9 times

Full Text: | Download PDF

Show Abstract
The amplitude‐independent acoustical mechanical quality factors Q of 99.95% pure polycrystalline molybdenum and tungsten have been measured as a function of temperature and heat treatment from 50 mK to 300 K. Data were obtained from 1 kHz torsional modes of resonators designed to minimize extraneous loss effects. Thermal annealing at temperatures above the recrystallization temperatures yielded strongly enhanced Q. Maximum Q values of 4.38×107 in Mo and 1.23×107 in W were observed in annealed material at the lowest measurement temperatures. Internal friction peaks and backgrounds are discussed. The temperature dependence of the resonator frequency is reported. Mo and W are compared with Al‐5056 as suitable materials for fabrication of cryogenic resonant‐bar gravity‐wave antennas.
Show PACS
62.40.+i Anelasticity, internal friction, stress relaxation, and mechanical resonances
04.80.-y Experimental studies of gravity

Activity and diffusivity of oxygen in liquid Ag‐Yb1Ba2Cu3 and Tl1Ba2Ca2Cu3 alloys

H. Chou, H. S. Chen, W. C. Fang, and M. K. Wu

J. Appl. Phys. 72, 5635 (1992); http://dx.doi.org/10.1063/1.351963 (7 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
We have measured the activity and diffusivity of oxygen in liquid Ag‐Yb1Ba2Cu3 and Tl1Ba2Ca2Cu3 at 930 and 900 °C, respectively, by a modified coulometric titration method on the galvanic cell: O in liquid alloys/yttria stabilized zirconia/air, Pt. The standard Gibbs formation energy and the diffusivity of oxygen in liquid Ag‐Yb1Ba2Cu3 alloy for 1/2O2(1 atm)→O(1 at. %) are determined to be ΔG=−247.4 kJ/g atom, and D=1.52×10−4 cm2/s. The oxygen solubility Cs in the Ag‐Yb1Ba2Cu3 alloy is 0.0913 at. %, a factor of 5.5 higher than that in Yb1Ba2Cu3 alloy. The addition of Ag does not alter the growth mechanism and the oxygen diffusion controls the film growth. The growth speed is enhanced as a result of the enhanced oxygen solubility. ΔG and the diffusion coefficient of oxygen in the Tl1Ba2Ca2Cu3 liquid alloy are −257 kJ/g atom and 1.2×10−4 cm2/s, respectively. The oxygen solubility of the Tl1Ba2Ca2Cu3 alloy at 900 °C is found to be very high at ∼5.74 at. %. All thermodynamic data for oxygen in the precursor alloys are consistent with each other but there is a deviation of activity coefficient with composition for the different alloys from the theoretical model.
Show PACS
65.40.De Thermal expansion; thermomechanical effects
66.10.-x Diffusion and ionic conduction in liquids
74.78.-w Superconducting films and low-dimensional structures
81.15.-z Methods of deposition of films and coatings; film growth and epitaxy

The effects of As overpressure and diffusion source on the diffusion of Mn in GaAs

C. H. Wu and K. C. Hsieh

J. Appl. Phys. 72, 5642 (1992); http://dx.doi.org/10.1063/1.351964 (7 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Data are presented to show the effect of As overpressure on the diffusion of Mn in GaAs using four different Mn sources. These sources include solid Mn thin film deposited directly on the GaAs substrate and Mn vapors from pure Mn, MnAs, and Mn3As solids. In the circumstance for which a solid Mn film is used as the diffusion source, a nonuniform doping distribution and poor surface morphology is obtained due to a reaction between the Mn film and the GaAs matrix. The degraded surface consists of a layer of polycrystalline cubic alloy having a lattice constant of nearly 8.4 Å and a composition close to MnGa2 with a small amount of As. Of the remaining diffusion sources (Mn, MnAs, and Mn3As), only MnAs consistently produces a uniform doping distribution and smooth surface morphology. For diffusions at 800 °C, a uniform surface hole carrier concentration as high as 1020/cm3 can be obtained using MnAs as the source. The As overpressure is found to drastically alter the Mn diffusion profile, and Mn, like Zn, may diffuse in GaAs interstitial‐substitutionally. Vapor from both the Mn and Mn3As solids degrade the GaAs surface. Mn3As, however, uncharacteristically degrades the surface more rapidly although the details of such are not well understood. With the presence of a high As overpressure, however, both surfaces of the Mn and Mn3As sources are converted to (Mn,As) compounds, the compositions being close to MnAs. High enough As overpressures are shown to completely suppress the GaAs surface degradation which is evident when Mn3As alone is used as the diffusion source.
Show PACS
66.30.J- Diffusion of impurities
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
61.72.sd Impurity concentration
61.72.sh Impurity distribution
61.72.sm Impurity gradients

Investigation of the transitional pore structure of activated carbon fibers by small‐angle neutron scattering

John Kieffer

J. Appl. Phys. 72, 5649 (1992); http://dx.doi.org/10.1063/1.351965 (8 pages) | Cited 1 time

Full Text: | Download PDF

Show Abstract
The small‐angle neutron scattering technique was used to determine the geometry of transitional pores in activated carbon fibers, as a function of the degree of activation. A refined numerical method for the data reduction is introduced. This procedure allows one to determine the characteristic size of structural features from density‐density correlation functions. Based on this analysis, the activation of the fibers can be described as an erosion process, producing a microporous granular structure. The largest structural features have a radius of gyration of approximately 260 Å. These define the pore structure. The size of these granules is reduced as the activation treatment progresses and the specific surface area increases. A smaller feature, with a radius of gyration of close to 80 Å, was also observed. The size of this structural element is not affected by the activation process. The description of the pore structure within the bulk of the fibers, as deduced from the scattering data, is consistent with scanning electron microscope pictures of the surface of the fibers.
Show PACS
61.05.fg Neutron scattering (including small-angle scattering)
81.05.Rm Porous materials; granular materials
68.35.-p Solid surfaces and solid-solid interfaces: structure and energetics

Structural properties of CuInxGa1−xSe2 thin films prepared by rf sputtering

Toshiyuki Yamaguchi, Jiro Matsufusa, and Akira Yoshida

J. Appl. Phys. 72, 5657 (1992); http://dx.doi.org/10.1063/1.351966 (6 pages) | Cited 14 times

Full Text: | Download PDF

Show Abstract
Cu‐In‐Ga‐Se alloy thin films were prepared by rf sputtering from powder targets previously synthesized by reacting Cu, In, Ga, and Se in the various ratios. From x‐ray diffraction analyses, these thin films have chalcopyrite structure of CuInxGa1−xSe2, and the lattice parameters (a and c) are varied linearly with indium content x in the thin films from CuInSe2 to CuGaSe2. The preferred orientation factor f(112) in these thin films was estimated. Its value was always more than 0.79, specifically 0.96 in a CuInSe2 thin films. From scanning electron microscope images, the grain sizes in these thin films decrease with the decrease of indium content. From x‐ray photoelectron spectroscopy analyses, the binding energies of the Se 3d, In 3d5/2, Cu 2p3/2 and Ga 2p3/2 in these thin films shifts to higher energies with decreasing indium content, where a slight bowing behavior is observed.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Cd Deposition by sputtering
79.60.Jv Interfaces; heterostructures; nanostructures

Growth of epitaxial TiN films on MgO(100) by high current discharge plasma

S. Miyagawa, K. Saitoh, H. Niwa, M. Ikeyama, G. Massouras, and Y. Miyagawa

J. Appl. Phys. 72, 5663 (1992); http://dx.doi.org/10.1063/1.351915 (5 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
High current discharge plasma produced by the Ta‐LaB6 cathode was used for ion plating of TiN films. The dependence of the deposition rate of TiN on the substrate dc bias potential was measured using the Rutherford backscattering spectrometry (RBS) method. The results indicate that the particles impinging on the substrate, i.e., vaporized particles (Ti) and reactive gases (N2), could be ionized at high efficiency of 70%. Epitaxial TiN films were grown at temperatures between 400 and 700 °C on cleaved MgO(100) substrate supplied with negative dc anf rf potential. Structures of the epitaxial film were investigated by RBS and ion channeling, and scanning tunneling microscope (STM). The minimum channeling yields for (100) and (110) axes obtained at a substrate temperature of 550 °C with the growth rate of 40 Å/s were found to be 1.4% and 2.0%, respectively, which were almost the same as that of the MgO substrate. Atomically resolved tunneling images of (100) surface of the epitaxial TiN film were observed by STM.
Show PACS
68.55.-a Thin film structure and morphology
81.15.Jj Ion and electron beam-assisted deposition; ion plating
07.79.Cz Scanning tunneling microscopes
61.05.-a Techniques for structure determination

SnO2 grazing‐incidence antireflection films for monochromatization of synchrotron radiation: Design, preparation, and characterization

H. Homma, M. Kentjana, E. E. Alp, T. M. Mooney, E. Witthoff, and T. Toellner

J. Appl. Phys. 72, 5668 (1992); http://dx.doi.org/10.1063/1.351916 (8 pages) | Cited 6 times

Full Text: | Download PDF

Show Abstract
Grazing‐incidence antireflection (GIAR) films are used to suppress electronic reflectivity, while maintaining good nuclear resonant reflectivity to help monochromatize the synchrotron radiation down to the μeV level of energy resolution. Such monochromators will have superior throughput by a factor of 100–500 compared to natural linewidth of individual nuclei. 119SnO2 GIAR films of various thicknesses were designed and fabricated on Pd‐coated quartz substrates. The performance of these films was evaluated based on the measurement of off‐resonance x‐ray reflectivity using MoKα radiation and conversion electron Mössbauer spectroscopy. A Pd film was deposited on a quartz substrate at room temperature and was subsequently annealed at 500 °C in an Ar atmosphere at a substrate temperature of 200 °C, SnO2 was sputtered onto the Pd by reactive sputtering in an Ar and O2 atmosphere. Employing quantitative analysis of surface and interface roughness, a series of experiments was also conducted to determine optimal sputtering conditions.
Show PACS
68.55.-a Thin film structure and morphology
42.79.Bh Lenses, prisms and mirrors
41.85.Si Particle beam collimators, monochromators
81.15.Cd Deposition by sputtering

Relationship between the stress and bonding properties of amorphous SiNx:H films

S. Hasegawa, Y. Amano, T. Inokuma, and Y. Kurata

J. Appl. Phys. 72, 5676 (1992); http://dx.doi.org/10.1063/1.351917 (6 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
Amorphous SiNx:H (a‐SiNx:H) films were deposited at 300 °C on single‐crystal Si and fused quartz substrates using SiH4‐NH3 mixtures. The stress and vibrational absorption were investigated as a function of the N content x. Increased tensile stress subsequent to a reduction in the compressive stress with increasing x was observed. From the values of stress determined for films on two different substrates, values of Y/(1−ν) for a‐SiNx:H films were estimated, where Y is Young’s modulus and ν the Poisson ratio. The values of Y/(1−ν) rapidly decreased with an increase in x, from 4.2×1012 dyn/cm2 for a‐Si:H films to about 2.5×1011 dyn/cm2 for a‐SiNx:H films having x above 1.0. It was found that the measured tensile stress in a‐SiNx:H films for high x above 1.0 was caused by the intrinsic stress, and that incorporated NH bonds act to relax the intrinsic stress. These results were discussed in terms of the change in the bonding configuration as a function of x, based on a modified random bonding model.
Show PACS
68.60.Bs Mechanical and acoustical properties
61.43.Fs Glasses
61.43.-j Disordered solids
61.44.Br Quasicrystals
68.55.-a Thin film structure and morphology

Epitaxial Fe/Cu superlattices on Si(111)

W. H. Schreiner, D. H. Mosca, S. R. Teixeira, and N. Mattoso

J. Appl. Phys. 72, 5682 (1992); http://dx.doi.org/10.1063/1.351918 (5 pages) | Cited 3 times

Full Text: | Download PDF

Show Abstract
We report on the successful epitaxial growth of Fe/Cu superlattices on Si(111) wafers at room temperature. The superlattices were characterized with x‐ray diffraction, conversion electron Mössbauer spectrometry, and selected area electron diffraction experiments. The epitaxial growth is crucially dependent on which element is deposited first on the bare Si(111).
Show PACS
68.65.-k Low-dimensional, mesoscopic, nanoscale and other related systems: structure and nonelectronic properties
75.70.-i Magnetic properties of thin films, surfaces, and interfaces

Compaction, distribution, and chemical bonding of tungsten‐implanted glassy carbon

A. Hoffman, P. J. Evans, D. D. Cohen, and P. J. K. Paterson

J. Appl. Phys. 72, 5687 (1992); http://dx.doi.org/10.1063/1.351919 (8 pages) | Cited 8 times

Full Text: | Download PDF

Show Abstract
The composition, distribution, and chemical bonding of tungsten‐implanted glassy carbon have been studied for ion doses between 3.5×1014 and 1.5×1017 ions/cm2. The implantations were performed using a metal‐vapor vacuum arc ion source which for an extraction potential of 20 kV yields a mean implant energy of 60 keV. The implanted layer was examined by Rutherford backscattering spectrometry and Auger profiling spectroscopy. In addition, volume effects were assessed by measuring the step height between implanted and unimplanted regions. It has been established that the implanted tungsten is bonded in a carbidic configuration. This is in agreement with thermodynamic data which favors carbide formation rather than separate phases of metallic tungsten and graphitic carbon. For the highest dose studied, 1.5×1017 ions/cm2, the tungsten distribution was found to be nearly constant near the surface followed by a decrease at larger depths. For ion doses up to 3.6×1016 ions/cm2, the maximum tungsten distribution was found to occur at a depth 300±100 Å and the implanted and retained doses were found to be equal. For tungsten ion doses between 7.35×1014 and 1×1016 ions/cm2, the implanted region was found to be compacted by 300±100 Å. The latter is attributed to an irradiation‐induced densification of glassy carbon from 1.5 to 2.1 g/cm3. This compaction effect is also found to occur upon C+ (30 keV) implantation for ion doses between 3×1016 and 1.3×1017 ions/cm2. In this case the implanted layer was compacted by 400±100 Å. For higher tungsten doses, a steep increase in compaction of the tungsten implanted layer was observed. This is attributed to chemical and sputtering effects.
Show PACS
68.55.Ln Defects and impurities: doping, implantation, distribution, concentration, etc.
68.55.Nq Composition and phase identification
61.72.up Other materials

Effects of doping variations on electron transport in GaAs n+‐n‐n+ structures

H. Tian, K. W. Kim, M. A. Littlejohn, U. K. Mishra, and M. Hashemi

J. Appl. Phys. 72, 5695 (1992); http://dx.doi.org/10.1063/1.351920 (7 pages) | Cited 5 times

Full Text: | Download PDF

Show Abstract
Electron transport properties in GaAs n+‐n‐n+ structures with varying doping profiles (in the direction of electron transport) are investigated using self‐consistent ensemble Monte Carlo simulations. In particular, we study the effects of ramp doping [i.e., linearly increasing (ramp‐up) or decreasing (ramp‐down) doping density within the n region] and spike doping (i.e., introducing one or more n+ spikes in the n region) on electron transport to assess differences, advantages, and potential applications of these doping profiles on device performance. Underlying physical mechanisms for electron transport in these structures are analyzed. Simulation results reveal that overall electron transport can be improved significantly by employing ramp‐up (rather than ramp‐down) doping and multispike (instead of single‐spike) doping schemes. Potential advantages of variable doping in field‐effect transistor applications include enhanced current drive capability, reduced source resistance, and improved breakdown characteristics.
Show PACS
72.80.Ey III-V and II-VI semiconductors
73.40.Kp III-V semiconductor-to-semiconductor contacts, p-n junctions, and heterojunctions
85.30.Tv Field effect devices
61.72.U- Doping and impurity implantation

Electrical conduction in polyaniline compressed pellets doped with alkylbenzenesulfonic acids

Atsushi Kobayashi, Xinfei Xu, Hitoshi Ishikawa, Masaharu Satoh, and Etsuo Hasegawa

J. Appl. Phys. 72, 5702 (1992); http://dx.doi.org/10.1063/1.351921 (4 pages) | Cited 16 times

Full Text: | Download PDF

Show Abstract
Anion dependent processes of the electrical conduction in chemically prepared polyaniline compressed pellets doped with alkylbenzenesulfonate anion of alkyl chain length 1, 8, and 12 have been investigated by the measurement of the temperature dependence of the conductivity. The conductivity of the samples changes with the temperature as T−1/2, which shows the conduction followed a one dimensional variable range hopping process. With the increase of the alkyl chain length of the dopant anion, the conductivity of the heavily doped 50 mol % sample decreases in whole temperature range, but an exponential factor of the variable range hopping remains unchanged. The results concerning the alkyl chain length of the dopant anion have been discussed from the ‘‘quasi‐one dimensional’’ variable range hopping mechanism and demonstrated the decrease of the transverse localization length and the interchain transfer integral of electron.
Show PACS
72.80.Le Polymers; organic compounds (including organic semiconductors)
72.20.Jv Charge carriers: generation, recombination, lifetime, and trapping
61.72.up Other materials
Page 1 of 3 Pages Next Page | Jump to Page
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close