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  • 1
    Electronic Resource
    Electronic Resource
    Temperature dependence of photoluminescence from Mg-doped In0.5Ga0.5P grown by liquid-phase epitaxy (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 70 (1991), S. 2309-2312 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of photoluminescence from the Mg-doped In0.5Ga0.5P layers on (100) GaAs substrates grown by liquid-phase epitaxy has been studied. At low temperature, the spectra show only two major emission peaks involving intrinsic recombination and conduction–band-to-acceptor transition. The intrinsic recombination dominates in the doping concentration range studied (1.0×1017–7.0×1018 cm−3) above 60 K. Below 50 K, these two peaks merged with each other when the doping concentration is higher than 1×1018 cm−3. The temperature dependence of band gap in In0.5Ga0.5P layers determined from the photoluminescence peak energy varies as 1.976 − [7.5 ×10−4 T2/(T + 500)] eV. For the moderately doped concentration (p 〈 1.4 × 1018 cm−3), the Mg acceptor ionization energy obtained from 50-K photoluminescent spectra is in the range from 37 to 40 meV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.349425
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  • 2
    Electronic Resource
    Electronic Resource
    Uniaxial stress effects on the AlAs/GaAs double-barrier heterostructures (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 8241-8246 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have measured the current-voltage characteristics of GaAs-AlAs-GaAs-AlAs-GaAs double-barrier heterostructures grown by molecular beam epitaxy on (100) oriented substrates under longitudinal uniaxial stress along 〈100〉 (parallel to current) direction and transverse uniaxial stress along 〈011〉 (perpendicular to current) direction at 77 K. For longitudinal stress measurement, the peak-to-valley current ratio due to Γ conduction electrons and the peak voltage (the voltage where the current peaks) decrease essentially with longitudinal stress and the negative differential resistance (NDR) disappears at a stress that depends on the dopings and dimensions of the heterostructures. However, it is surprisingly recovered at very high stress and the peak voltage reappears at a lower voltage, which is quite in contrast with the previous report for hydrostatic pressure studies. The observed shifts of the peak voltage, the decrease of the peak current, and hence the disappearance of the NDR are consistent with pressure-induced increase of the effective mass. The recovery of Γ-NDR is explained by the more rapid reduction of Xl (momentum conserving longitudinal X valleys) nonresonant current due to the increase of reflections at GaAs/AlAs interfaces under very high uniaxial stress, where there are potential wells rather than barriers for Xl current. A distinct NDR near- zero bias (∼40 mV) appears when the externally applied uniaxial stress is high enough. This has been attributed by Mendez and Chang [Surf. Sci. 229, 173 (1990)] to the resonant tunneling between two-dimensional electron gases. Our experiment shows that this tunneling is via momentum conserving longitudinal X-valleys (Xl). For transverse stress measurement, there is no evidence of this feature up to 7 kbar.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347430
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  • 3
    Electronic Resource
    Electronic Resource
    Uniaxial stress dependence of the current-voltage characteristics of n-type AlAs/GaAs/AlAs tunnel diodes at 77 K (1991)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 69 (1991), S. 525-527 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Longitudinal uniaxial stress along 〈100〉 has been applied in AlAs-GaAs-AlAs resonant tunneling heterostructures grown on (100) substrates to study the current-voltage characteristics as a function of stress. We find that the nonresonant current is due to Fowler–Nordheim tunneling currents by both longitudinal and transverse X valleys (X1 and Xt). This current decreases with low stress (〈1 kbar), increases with intermediate stress and decreases with high stress (〉9 kbar) again. This is due to the increase of the Xt barrier at low stress, the decrease of the X1 barrier at intermediate stress, and the formation and the increase of X1 potential well depth at high stress. We also find a large unexplained monotonic decrease of the resonant current through the Γ valley.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.347699
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  • 4
    Electronic Resource
    Electronic Resource
    Piezoresistive response induced by piezoelectric charges in n-type GaAs mesa resistors for application in stress transducers (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 333-340 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The resistance change due to piezoelectric charge densities in n-GaAs mesa resistors has been studied as a function of surface stress. Those changes are verified by measuring some realized stress transducers with such resistors fabricated on the surface of micromachined thin GaAs membranes or GaInP/GaAs cantilever beams. It is shown here that the surface stresses induced by the deformation of cantilever beams can cause nonuniform stress distributions within the resistors, and the stress gradients consequently yield considerable piezoelectric charge densities that lead to an appreciable resistance change. In addition, this effect of piezoelectric charges is examined from several types of resistors that have a different doping, direction, thickness h, and width-to-thickness ratio L/h. According to those results, optimization of this mechanism is related to the doping and geometrical design of GaAs mesa resistors. In addition to the effect of piezoelectric charges, mobility change can affect the resistance as well. The resistance changes observed from the low doped resistors exhibit an opposite sign for the resistors oriented along [011] and [011¯] directions. These directional-dependent characteristics confirm that the effect of piezoelectric charges indeed exists in mesa resistors. Fitting the width-dependent sensitivities measured in experiments allows us to estimate each contribution of these two effects. For the [011¯] oriented resistors with L/h of 10, and ns of 4.8×1011, the sensitivity of relative resistance change as high as 92.7%/GPa is obtained. Results in this study demonstrate that the resistance change in n-GaAs mesa resistors is attributed to the effects of piezoelectric charges and mobility change. Moreover, GaInP/GaAs material system with its piezoresistive response originated from piezoelectric charges is highly promising in III–V compound semiconductor stress transducers. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.369452
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  • 5
    Electronic Resource
    Electronic Resource
    Lichen planus with xanthomatous change in a patient with primary biliary cirrhosis (2000)
    Oxford, UK : Blackwell Science Ltd
    British journal of dermatology 142 (2000), S. 0 
    Details
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2133.2000.03317.x
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  • 6
    Electronic Resource
    Electronic Resource
    Structural and magnetic studies of Er2Fe17−xMxCy (M=Ga and Al) compounds : The 40th annual conference on magnetism and magnetic materials (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 5533-5535 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of Ga and Al substitution for Fe on the structural and magnetic properties of the Er2Fe17−xMxCy (M=Ga, Al; x=0–4, y=0–2) compounds was investigated. It was found that Ga is superior to Al in stabilizing the single-phase Er2Fe17−xMxCy compounds. The hexagonal Th2Ni17-type structure persisted in almost all alloys with the exception of Er2Fe13Ga4C and Er2Fe13Ga4C2. These two compounds exhibited a rhombohedral Th2Zn17 structure. Both the Curie temperature and magnetization can be enhanced with a certain amount of Ga or Al substitution. But they decreased almost monotonically with the increase of Ga or Al content in Er2Fe17−xMxCy (x(approximately-greater-than)1, y(approximately-greater-than)0). The spin reorientation temperature, Tsr, was influenced by both carbon interstitial and Ga or Al substitution for Fe and ascribed to the increase of the c-axis uniaxial anisotropy of the Er3+ sublattice by the modification of electron structure around it. The highest Tsr of 241 K appears in the compound Er2Fe14Ga3C. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362300
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  • 7
    Electronic Resource
    Electronic Resource
    Resonant indirect Fowler–Nordheim tunneling in Al0.8Ga0.2As barrier (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 266-268 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Oscillatory current-voltage characteristics of n+-GaAs/semi-insulating Al0.8Ga0.2As/nGaAs heterojunction barriers (400 A(ring) thick) grown by molecular beam epitaxy on n+-GaAs (100) substrates are observed at 4 K when the heterostructures are placed under the transverse uniaxial stress along 〈011〉 direction (perpendicular to current direction) above 4 kbar. We attribute these oscillations to the resonant indirect Fowler–Nordheim tunneling via 〈011〉 oriented transverse X valleys, where the change of wave vector is required for tunneling.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104684
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  • 8
    Electronic Resource
    Electronic Resource
    Accelerated formation of 110 K high Tc phase in the Ca- and Cu-rich Bi-Pb-Sr-Ca-Cu-O system (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 779-781 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The crystal structure and superconducting properties of the Bi-Pb-Sr-Ca-Cu-O system with Ca- and Cu-rich nominal composition were investigated. A nearly single-phased 110 K high Tc superconductor can be obtained with 852 °C/20 h sintering from the starting composition of Bi1.7Pb0.4Sr1.6Ca2.4Cu3.6Oy. X-ray diffraction patterns, resistivity measurement, diamagnetic susceptibility results, and scanning electron micrographs all indicate that the Ca- and Cu-rich nominal composition would result in better superconducting properties than those of Ca:Sr=1:1 Bi-Pb-Sr-Ca-Cu-O compounds in a much shorter sintering time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.103315
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  • 9
    Electronic Resource
    Electronic Resource
    Uniaxial stress dependence of current-voltage characteristics in GaAs-AlxGa1−xAs-GaAs heterojunction barriers (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 55 (1989), S. 1336-1338 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Current-voltage characteristics of nGaAs-iAlxGa1−xAs-nGaAs heterojunction barriers grown on (100) substrates have been measured under uniaxial stress along 〈100〉 at 77 K. The results show that thermionic emission current through longitudinal X valleys becomes dominant over Fowler–Nordheim tunneling current through Γ or transverse X valleys, as stress increases. From the stress-dependent thermionic emission current the rate of change with stress of the band-edge energy difference between Γ in GaAs and longitudinal X in AlGaAs is deduced to be 14±2 meV/kbar, which leads to an X-valley shear deformation potential of 9.6±1.8 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.101648
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of electron energy distribution in a GaAs vertical field-effect transistor with hot-electron injection (1989)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 54 (1989), S. 274-276 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Electron energy distribution on the drain edge of a channel in a GaAs nongated vertical field-effect transistor with hot-electron injection has been probed using hot-electron spectroscopy as a function of current density up to about 105 A/cm2. Electrons rapidly accelerated in an n+-i-p+-i-n+ planar-doped barrier source exhibit nonequilibrium transport through a thin channel (130 nm) with deceleration due to scattering and acceleration due to the electric field. The resulting hot-electron energy distribution, determined by using a planar-doped barrier as an analyzer, diverges from the steady-state one. This divergence dramatically increases with increasing the current density.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.100988
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