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  • 1
    Electronic Resource
    Electronic Resource
    Measurement of thermal diffusivity based on the photothermal displacement technique using the minimum phase method (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 588-590 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method of measuring the thermal diffusivity of solid material at room temperature using photothermal displacement is proposed. The influence of the parameters, such as the radius and modulation frequency of the pump beam and the sample thickness, was studied. From the minimum position of phase of measured deflection with respect to the pump beam, the thermal diffusivity of the materials can be obtained. The position where phase has the minimum value is determined using multiparameter least-square regression fitting. The experimental values for different samples obtained by applying the method are in good agreement with the literature values. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373700
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  • 2
    Electronic Resource
    Electronic Resource
    Studies of ZnSe-based semiconductor thin films using grazing incidence x-ray scattering and diffraction (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 237-243 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Grazing incidence x-ray scattering and x-ray diffraction techniques have been employed to investigate the microstructures in various ZnSe-based semiconductor thin films grown on GaAs substrates by molecular beam epitaxy and metalorganic chemical vapor deposition methods. The results are also used for a comparison of the interfacial roughness and overall quality of the II–VI thin films prepared by these two different growth methods. Structural parameters such as the interfacial roughness and layer thickness obtained from the scattering measurements and lattice constants obtained from the x-ray diffraction pattern around the GaAs(004) peak can be correlated with the film deposition rate, compound composition, and lattice strain in the epilayers. We thus demonstrate that x-ray scattering techniques in conjunction with diffraction measurements are useful tools for nondestructive characterization of buried interfaces in semiconductor layer materials. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.369434
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  • 3
    Electronic Resource
    Electronic Resource
    Optical and electrical characterization of nitrogen ion implanted ZnSSe/p-GaAs (100) (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 4994-4999 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Nitrogen ions were implanted into ZnSxSe1−x epilayers grown on p-GaAs (100) substrates by molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD). Dopant activation and annealing out the implant damage were achieved by a postannealing process in a N2 ambient. Schottky structures employing the implanted p-type ZnSxSe1−x were fabricated and device efficacy was examined by photoluminescence (PL) spectroscopy, current–voltage (I–V), current–voltage temperature (I–V–T), and high frequency capacitance–voltage (C–V) measurements. PL spectra showed a clear donor–acceptor pair (DAP) recombination at an energy of 2.735 and 2.72 eV, in both MBE and MOCVD ZnSSe epilayers, respectively, regardless of the postannealing temperatures. The diode conduction in forward bias proceeds by the combination of thermionic and tunneling emission. C–V measurement proved the maximum doping concentration to be around 1017 cm−3 after ion implantation. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.366368
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  • 4
    Electronic Resource
    Electronic Resource
    Nitrogen ion implanted ZnSe/GaAs p-i-n photodetectors (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 2328-2333 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: p-i-n photodiodes were fabricated on nitrogen ion implanted undoped ZnSe/n-type ZnSe epilayers grown on n+GaAs (100) substrates by molecular beam epitaxy. To obtain a quasi-uniform p layer doping profile, nitrogen ions at multiple energies and ion doses were implanted at room temperature. The activation of implanted species was carried out by an optimized post-annealing in a nitrogen ambient. Optical studies were performed on the implanted/annealed devices by photoluminescence spectroscopy at 10 K, which indicated donor–acceptor pairs at an energy of 2.7 eV and its phonon replicas with 30 meV intervals. The circular p-i-n diodes with a 1 mm diam contact area showed a device breakdown voltage to be linearly dependent on the thickness of the undoped ZnSe epilayer. For p-i-n diodes fabricated on an initial 0.5 μm thick undoped ZnSe layer, an ideality factor of 1.19 and a reverse bias breakdown voltage of 12 V was observed. A large photocurrent, good linearity with light intensity, and low dark current were observed. A photocurrent/dark current ratio 〉105 was obtained at an illumination intensity of 100 mW/cm2. These devices exhibited a responsivity of 0.025 A/W at a wavelength of 460 nm through the top 200 Å thick metal contacts.© 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368300
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  • 5
    Electronic Resource
    Electronic Resource
    Ordering effect on band-gap lowering in lattice-matched InAlAs epilayers grown on InP by metal–organic chemical-vapor deposition (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 1905-1907 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Band-gap lowering due only to the cation ordering effect is investigated in InAlAs layers grown on InP by using photoluminescence measurement. Double-crystal x-ray diffraction and Rutherford backscattering measurements confirm that both of the InAlAs epilayers studied, grown at 700 and 750 °C, are lattice matched with InP substrates. Through transmission electron diffraction measurements, it is observed that a CuPt-type ordering structure is formed in the InAlAs layers grown at 700 °C but not in the layers at 750 °C. Photoluminescence measurements at 1.7 K reveal that the band-gap energy of the ordered InAlAs is smaller by 60 meV than that of the unordered InAlAs. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121222
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  • 6
    Electronic Resource
    Electronic Resource
    Optical properties of InGaAs linear graded buffer layers on GaAs grown by metalorganic chemical vapor deposition (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 2973-2975 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report optical characteristics of linear graded InxGa1−xAs (XIn=0–0.58) buffer layers grown on GaAs by low-pressure metalorganic chemical vapor deposition. Two types of wirelike surface structures were observed from the layers grown at two different temperatures. Low-temperature photoluminescence (PL) and double-crystal x-ray diffractometric measurements indicate that the PL energy and the relaxation of the graded layers were strongly dependent on the top surface structure. InGaAs cap layers were grown on top of the graded buffer layers with a variation of indium composition. A strong PL signal was observed from the top region of the graded layer grown with a lattice-matched cap layer. It suggests that the top region of the grade, similar to a graded well structure, is compressively strained but is of high structural quality without dislocations. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116373
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  • 7
    Electronic Resource
    Electronic Resource
    Large non-biased all-optical bistability in an electroabsorption modulator using p-i-n-i-p diode and asymmetric Fabry–Perot cavity structure (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 3216-3217 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have constructed a non-biased all-optical bistable device using electroabsorption in multiple quantum wells (MQWs). The device is made of a serial connection of two identical double p-i-n (p-i-n-i-p) diode structures within asymmetric Fabry–Perot (AFP) cavity. This scheme ensures both large internal electric field swing and full exploitation of the light intensity. From the measurement of the diode properties, the non-biased bistability parameters—reflection change of 19%, contrast ratio of 17:1, and bistable loop width of 70%—were obtained. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116441
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  • 8
    Electronic Resource
    Electronic Resource
    High-Tc edge junctions with a Ga-doped YBa2Cu3O7−δ barrier and interface resistances (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 2053-2055 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High-Tc ramp-edge junctions with a Ga-doped YBa2Cu3O7−δ barrier have been fabricated in the trilayer geometry of YBa2Cu3O7−δ/YBa2Cu2.79Ga0.21O7−δ/YBa2Cu3O7−δ on LaAlO3 single crystals. Interface resistances of the junctions were drastically reduced by using an in situ Ar plasma cleaning treatment. The Ga-doped YBa2Cu3O7−δ junctions with barrier thickness of 200 and 300 Å clearly exhibited resistively-shunted-junction-like current–voltage characteristics. The critical currents of the Ga-doped junctions were less sensitive to the variation of the barrier thickness compared to those of the other junctions. The increase of the barrier resistivity by Ga-doping and the in situ rf plasma cleaning treatment resulted in an enhancement of the junction reliability and reproducibility. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.123754
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  • 9
    Electronic Resource
    Electronic Resource
    Correlation of optical and structural properties of light emitting porous silicon (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 855-857 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Microscopic structures of light emitting porous silicon layers have been studied. The samples prepared in an aqueous HF solution by anodizing p-type silicon substrates show a strong positional dependence of photoluminescence and Raman spectra. The photoluminescence peaks are broad around 1.8 eV, where the photoluminescence intensities are comparable to that of GaAs at 5 K. We have found from Raman studies showing two characteristic peaks at 500 and 520 cm−1 that microscopic structures reveal gradual changes from porous silicon to a mixture of polycrystalline and hydrogenated amorphous phases as the probing spot is moved to the edge of the sample. This is explained by the redeposition of silicon atoms on top of the porous silicon layers near the edge of the sample as a result of liquid flow caused by bubbles of hydrogen gas which was produced near the surface of the sample during the anodization process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109605
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  • 10
    Electronic Resource
    Electronic Resource
    Carbon Dioxide as Hydrogen Acceptor in Dehydrogenation of Alkanes (1972)
    s.l. : American Chemical Society
    Industrial and engineering chemistry 11 (1972), S. 444-446 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/i360044a017
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