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  • 1
    Electronic Resource
    Electronic Resource
    Spontaneous formation of Al rich and Ga rich AlxGa1−xAs/AlyGa1−yAs superlattice and strong enhancement of optical properties (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 65 (1994), S. 1921-1923 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Long range composition ordering and spontaneous formation of Al rich and Ga rich AlxGa1−xAs/AlyGa1−yAs superlattice were demonstrated. This was observed by cross-sectional transmission electron microscopy (TEM) in a 280 A(ring) Al0.4GaAs quantum well laser diode heterostructure with Al0.7GaAs barriers grown on (111)B GaAs substrates. On the contrary, none of above superstructure was observed by TEM on a side-by-side grown (100) oriented substrate. More evidence is shown in the (111)B Al0.7GaAs barriers which were disordered due to a high growth temperature and did not show any superstructure. 10 K photoluminescence was shown with 32 meV redshift and a 12-times peak intensity enhancement in (111)B orientation. © 1994 American Institue of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.112817
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  • 2
    Electronic Resource
    Electronic Resource
    Optical and structural properties of spontaneously formed long-range compositional modulation in (111)A and (111)B AlGaAs (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8669-8674 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the spontaneously formed long-range Al-rich and Ga-rich AlxGa1−xAs/AlyGa1−yAs superlattices in both (111)A and (111)B AlGaAs during epitaxial growth. The spontaneously formed compositional modulation has been investigated by cross-sectional transmission electron microscopy in AlxGa1−xAs (x=0.3–0.4) grown on (111)A and (111)B GaAs substrates at 600–700 °C. In contrast, similar superstructures are not observed in layers simultaneously grown on (100) substrates. The observed structural compositional modulation is closely related to the large peak energy redshift and peak intensity enhancement in 15 K photoluminescence (PL) of samples grown on both (111)A and (111)B orientations to those on (100). The respective redshifts of PL peak energy for (111)A and (111)B Al0.27Ga0.73As to that of (100) are 137 and 45 meV, while the PL integrated intensity enhancement to (100) amounts to 200 and 2000 times, respectively. The effect of compositional modulation is reduced with the increasing growth temperatures as shown in the considerably less compositionally modulated (111)A and (111)B Al0.40Ga0.60As grown at 700 °C. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362492
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  • 3
    Electronic Resource
    Electronic Resource
    Molecular beam epitaxial GaAs optical detectors on silica fibers (1988)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 52 (1988), S. 1768-1770 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: By using molecular beam epitaxy and post-growth annealing techniques, we have successfully made GaAs interdigitated photoconductive detectors on D-shaped silica fibers. The detectors exhibit low leakage current and internal photoconductive gains of up to 15 are measured. To our knowledge this is the first realization of active III-V optoelectronic devices on fibers and opens up the possibility of realizing optoelectronic integration and circuits directly on fibers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.99620
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  • 4
    Electronic Resource
    Electronic Resource
    Performance characteristics of InGaAs/GaAs and GaAs/InGaAlAs coherently strained superlattice photodiodes (1987)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 51 (1987), S. 1164-1166 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The properties of In0.24Ga0.76As/GaAs and GaAs/In0.05Ga0.58Al0.37As superlattice photodiodes grown by molecular beam epitaxy have been investigated. From the temporal response characteristics, deconvolved rise times ∼60–100 ps are obtained. The measured responsivities of the photodiodes with dark currents of 5–10 nA at 10 V are ∼0.4 A/W, which correspond to peak external quantum efficiencies of ∼60%. These results indicate that very high performance photodiodes can be realized with strained layers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.98720
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  • 5
    Electronic Resource
    Electronic Resource
    Temperature-dependent transport properties of n+ GaAs/low-temperature GaAs/n+ GaAs structures grown by molecular beam epitaxy (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8488-8492 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The temperature-dependent I–V characteristics of n+ GaAs low-temperature GaAs(AlGaAs) n+ GaAs structures in which the low-temperature layers were grown at 250, 350, and 450 °C were analyzed. Band conduction with an activation energy of 0.72 eV dominates at T(approximately-greater-than)250 K. Hopping conduction dominates at T〈250 K, where the resistivity was found to be insensitive to temperature. From this analysis, it is shown that Fermi level is pinned to an acceptorlike deep level of about 1017 cm−3, which lies at 0.72 eV below the conduction band. Measured capacitance can be described in terms of a parallel-plate capacitance with separation being equal to the expected growth thickness. Majority traps (electrons) were observed by deep-level transient spectroscopy with an activation energy about 0.72 eV, confirming the result of the resistivity analysis. In addition, the I–V characteristics were fitted to the simulated curves based on a simplified space-charge limited theory and the result was found to be consistent with the resistivity analysis. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.362525
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  • 6
    Electronic Resource
    Electronic Resource
    Traps in molecular-beam epitaxial In0.53(GaxAl1−x)0.47As/InP (1990)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 67 (1990), S. 2450-2453 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Deep-level transient spectroscopy measurements have been made on molecular-beam epitaxial In0.53(GaxAl1−x)0.47As lattice matched to InP. Several electron and hole traps, with activation energies ranging from 0.14 to 0.79 eV, have been identified and characterized. In particular, systems of electron traps (0.30≤ΔET≤0.79 eV) and hole traps (0.14≤ΔET≤0.31 eV) with monotonically changing activation energies have been identified in these alloys. We believe these traps are dominant in this alloy system.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.345492
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  • 7
    Electronic Resource
    Electronic Resource
    Growth of GaAs on SiOx by molecular-beam epitaxy (1987)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 62 (1987), S. 1416-1419 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have investigated the molecular-beam epitaxial growth and photoluminescence properties of GaAs on SiOx. It is seen that material with a grain size of 0.6–0.8 μm can be grown directly on the dielectric. The properties improve further when the layers are short-term annealed with a halogen lamp. Optimum grain sizes of 1.6 μm are obtained when the as-grown material is annealed at 950 °C for 10 s, and very strong luminescence is observed in the same material. Photoconductive detectors made on the overgrown GaAs show large responsivities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.339855
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  • 8
    Electronic Resource
    Electronic Resource
    High quality epitaxial Si grown by a simple low pressure chemical vapor deposition at 550 °C (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 1617-1619 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have designed a simple-hot wall low pressure chemical vapor deposition (LPCVD) system to grow high quality epitaxial Si films from 550 to 900 °C. The epitaxial film has been examined by scan electron microscopy for surface morphology, and by x-ray diffraction and cross-sectional transmission electron microscopy for crystallinity. Its quality has been found comparable to that of the substrate. Reduction of moisture and oxygen in the ambient is critical to the success of the growth at low temperatures. A combination of a leak-tight LPCVD reactor, a high flow rate of 61/min of H2 purge, and a pre-bake at high temperature of 950 °C has been used to achieve the reduction of moisture and oxygen. Degraded films form with increasing full width at half maximum of x-ray diffraction peak when a pre-bake at lower temperature is used. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117049
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  • 9
    Electronic Resource
    Electronic Resource
    Picosecond photoresponse of carriers in Si ion-implanted Si (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 653-655 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Picosecond photoresponse of carriers in Si ion-implanted Si samples has been measured using femtosecond transient reflectivity measurement. A threshold peak implant dose of 1016 cm −2 is required to achieve picosecond carrier lifetime. At this dosage, carrier lifetimes of 0.9 and 1.4 ps are measured for the as-implanted and 400 °C annealed Si substrates, respectively. The increase in carrier lifetime upon annealing is attributed to the reduction in the concentration of trap and recombination centers. Sheet resistance also shows a strong dependence on the annealing temperature. An eightfold increase in sheet resistance is obtained for annealed samples, and a reduction in hopping conduction, manifested by the e−1/T temperature dependence, may be responsible for the increase in resistance. Further evidence of decreasing hopping conduction can be also observed from the more than two orders of magnitude in reduction of sheet resistance as the peak dosage decreases from 1016 to 1014 cm−2. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.117795
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  • 10
    Electronic Resource
    Electronic Resource
    Observation of compositional modulation in (111)A InGaAs quantum wells and the effect on optical properties (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 69 (1996), S. 443-445 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the growth of InGaAs/GaAs multiple quantum wells (MQWs) on (111)A GaAs. Uniform thickness of (111)A quantum wells is observed by the cross-sectional transmission electron microscopy (TEM). Growth induced long-range In- and Ga-rich InxGa1−xAs/InyGa1−yAs superlattice in (111)A is also observed by cross-sectional TEM in the ternary InGaAs wells. In contrast, none of the above superstructure was observed by TEM on a side-by-side grown (100) oriented substrate. However, the photoluminescence (PL) linewidth is broadened by such compositional modulation. Low-temperature (15 K) photoluminescence showed a broad PL linewidth of 27.5 meV for In0.16Ga0.84As/GaAs MQWs grown on (111)A substrates at 520 °C. A decreased PL linewidth of 15.7 meV and a reduced compositional modulation in InGaAs wells can be achieved at a higher growth temperature of 560 °C. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118133
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