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  • 1
    Electronic Resource
    Electronic Resource
    Strain-induced band-gap modulation in GaAs/AlGaAs quantum-well structure using thin-film stressors (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 1763-1771 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effect of strain-induced band-gap modulation has been studied in a GaAs/AlGaAs multiple-quantum-well structure with the wells located at various depths in the structure. The energy change in the quantum wells was calculated based on simple elasticity theory and measured using photoluminescence on the structure where a thin-film stressor array was deposited. Metallic thin-film stressors were made by conventional thin-film deposition techniques followed by photolithography. It was found that the elasticity theory describes the energy changes reasonably well in comparison with the experimental results. For stressor layers that react with the heterojunction structure, the situation was more complex and requires more detailed analysis. Based on the calculated and experimental results it appears possible to fabricate quantum wire with lateral dimensions of less than 100 nm using thin-film technology and e-beam lithography. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360966
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  • 2
    Electronic Resource
    Electronic Resource
    Defect-assisted ohmic contacts on p-InP (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 2056-2060 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single-element contacts, Pd or Ni, on various p-InP substrates grown by liquid-encapsulation Czochralski (LEC) and by metal-organic chemical vapor deposition were investigated. Pd or Ni contacts on the substrates supplied by one certain manufacturer were found to be ohmic with a minimum contact resistivity of ∼5×10−5 Ω cm2 after annealing between 420 and 500 °C. However, ohmic behavior was not observed for these contacts on other substrates. Hall measurement, double-crystal x-ray diffractometry, and photoluminescence technique were used to evaluate the substrates. It was speculated that existence of intrinsic defects, such as P vacancies and other possible defects, in p-InP grown by LEC method may be responsible for the observed difference in ohmic behavior. A defect-assisted tunneling mechanism is proposed to account for the observed ohmic behavior of single-element contacts on certain p-InP substrates. This approach is potentially useful for making ohmic contacts to other compound semiconductors. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.358845
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  • 3
    Electronic Resource
    Electronic Resource
    Photoelastic waveguides and the controlled introduction of strain in III-V semiconductors by means of thin film technology (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 236-244 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the use of thin film technology to introduce controllable and thermally stable stress into semiconductor heterostructures. Two simple schemes are used. The first scheme is to use interfacial reactions between a metal and the substrate, such as Ni, Co, Pd, and Pt on GaAs/AlGaAs. The induced stress in the structure is reproducible and controllable because the volumetric change for a given reaction is fixed, as long as the deposited film is fully reacted to form a compound. The stability of the stress depends on the stability of the compound. In the case of Ni and Co on GaAs/AlGaAs, the induced stress is thermally stable up to 600 °C. Evaporated films and reacted films are usually under tension. The second scheme is to use rf sputtered W or WNi alloy films where W or WNi is sputtered onto a negative dc biased substrate. This scheme effectively provides highly compressed films. The thermal stability depends on the concentration of Ni in the WNi alloy. Using the two schemes above, we have fabricated low-loss (∼1 dB/cm at 1.52 μm wavelength) photoelastic waveguides in GaAs/AlGaAs heterostructures, and explored the interrelationship between the photoelastic waveguide characteristics and the stress. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360657
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  • 4
    Electronic Resource
    Electronic Resource
    Planar 1.3 and 1.55 μm InGaAs(P)/InP electroabsorption waveguide modulators using oxygen ion mixing and the photoelastic effect (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 4352-4361 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Efficient 1.3 and 1.55 μm InP-based electroabsorption waveguide modulators with planar device structures have been demonstrated. Elevated temperature oxygen ion implantation and/or the photoelastic effect induced by W metal stressor stripes deposited on the semiconductor surface have been used to produce these self-aligned planar guided-wave devices. The oxygen ion mixing process has been used to simultaneously achieve compositional disordering and electrical isolation of superlattice material while the photoelastic effect has been used to improve the lateral mode confinement. A 1.3 μm Franz–Keldysh modulator with a (approximately-greater-than)10 dB extinction ratio at 2 V and a 1.55 μm device with a (approximately-greater-than)10 dB extinction ratio at 7 V are reported. These single growth step planar processing techniques have also been used to fabricate relatively low-loss (〈4 dB/cm) double heterostructure InGaAs(P)/InP single-mode optical waveguides which demonstrate their usefulness in developing InP-based photonic integrated circuits.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355978
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  • 5
    Electronic Resource
    Electronic Resource
    Thermally stable PtSi Schottky contact on n-GaN (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 1275-1277 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Platinum silicide (PtSi) and Pt Schottky contacts on n-GaN have been investigated and compared. The PtSi contacts were formed on n-GaN by annealing a multilayer structure of Pt/Si with the appropriate thickness ratio at 400 °C for 1 h in forming gas. The barrier height of the as-formed PtSi contacts was found to be 0.87 eV capacitance–voltage (C–V), and remained unchanged after further annealing at 400 and 500 °C. Upon annealing at 600 °C for 1 h, the barrier height decreased to 0.74 eV (C–V), but the diodes remained well-behaved. The as-deposited Pt yielded a barrier height of 1.0 eV (C–V). Upon annealing at 400 °C for 1 h, the Pt diodes degraded and most of the diodes did not survive additional annealing at 400 °C for longer times. The electrical measurements and the Rutherford backscattering spectrometry results indicated that PtSi contacts are thermally much more stable than Pt contacts on GaN. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118551
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  • 6
    Electronic Resource
    Electronic Resource
    Planar semiconductor lasers using the photoelastic effect (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 83 (1998), S. 7442-7447 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Planar separate-confinement, double-heterostructure, single-quantum-well photoelastic GaAs/AlGaAs lasers have been fabricated using a novel yet practical processing technique involving thin-film surface WNi stressors for waveguiding and ion implantation for isolation. A p++-GaAs contact layer regrown by chemical beam epitaxy has been used to improve the WNi ohmic contacts to the lasers. Even without bonding on heat sinks, these planar photoelastic lasers operate at continuous wave at room temperature. The lowest threshold is 29 mA for a cavity length of 178 μm and a stressor width of 5 μm. The internal quantum efficiency above threshold is 75%. The characteristic temperature is 114 K. The main waveguiding mechanism of the photoelastic lasers is determined to be weak index guiding with the beam waist in the junction plane measured 10 μm behind the end facet. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.367988
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  • 7
    Electronic Resource
    Electronic Resource
    Ni and Ni silicide Schottky contacts on n-GaN (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 881-886 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electrical characteristics of Ni and NiSi Schottky diodes on n-GaN have been investigated as a function of annealing. Ni diodes were found to be stable up to 500 °C for 1 h in sequential annealing, with a barrier height φ (I–V) of 0.8–0.9 eV and an n factor of ∼1.1. The barrier height deduced from C–V measurements, φ (C–V), was typically 0.15 eV higher than φ (I–V). At 600 °C the diodes failed, and Ga was found to migrate into the Ni layer. NiSi diodes were stable up to 600 °C for 1 h, φ (I–V) was found to be about 0.8–1 eV with an n-factor of about 1.15. The value of φ (C–V) was between 0.3 to 0.6 eV higher than φ (I–V), consistent with the notion of the presence of a thin insulating layer at the NiSi/GaN interface. The electrical characteristics obtained in this study are also compared with those obtained for Pt and PtSi Schottky diodes on n-GaN. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368151
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  • 8
    Electronic Resource
    Electronic Resource
    The role of the tunneling component in the current–voltage characteristics of metal-GaN Schottky diodes (1998)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 84 (1998), S. 2099-2104 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature dependence of the current–voltage characteristics of Ni–GaN Schottky barriers have been measured and analyzed. It was found that the enhanced tunneling component in the transport current of metal-GaN Schottky barrier contacts is a likely explanation for the large scatter in the measured Richardson constant. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.368270
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  • 9
    Electronic Resource
    Electronic Resource
    Photoelastic AlGaAs/GaAs waveguide polarizer (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 63 (1993), S. 2047-2049 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: AlGaAs/GaAs double heterostructure transverse-electric (TE) waveguide polarizers, 5 mm long, with extinction ratios exceeding 20 dB and excess losses of 〈1 dB have been fabricated using simple thin film technology. The single-mode photoelastic waveguides were made by depositing either a thin Ni film (∼1000 A(ring)) with a 5-μm-wide window stripe pattern followed by thermal annealing or a thin W film (∼900 A(ring)) with a 5-μm stripe pattern using rf sputtering with the substrate under negative dc bias. The polarization mode selection is caused by the stress-induced birefrigence of the photoelastic waveguides. The change in dielectric constant due to stresses in the thin film structure was obtained from the experimental intensity output profile using an iterative calculation method. The tensile stress is 3×109 dyn/cm2 in the fully reacted Ni3GaAs stressor layer. The stress in the as-sputtered W films was compressive and decreased from 1×1010 dyn/cm2 to 4×109 dyn/cm2 after annealing between 300 and 500 °C for 30 min.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.110587
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  • 10
    Electronic Resource
    Electronic Resource
    Silicon on insulator photoelastic optical waveguide and polarizer (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 2016-2018 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Single-mode silicon on insulator photoelastic waveguides and polarizers have been investigated. It was found that waveguides induced by the photoelastic effect can be low loss (1.5 dB/cm at 1.53 μm) and can serve as polarizers as well. A polarization distinction ratio of 14 dB for both TE and TM mode has been obtained. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113677
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