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  • 1
    Electronic Resource
    Electronic Resource
    Transmission intensity oscillations in GaAs/AlAs superlattices induced by photogenerated charged transport
    Amsterdam : Elsevier
    Superlattices and Microstructures 15 (1994), S. 351 
    Details
    ISSN: 0749-6036
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1006/spmi.1994.1068
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  • 2
    Electronic Resource
    Electronic Resource
    High-power (2.2 W) cw operation of (111)-oriented GaAs/AlGaAs single-quantum-well lasers prepared by molecular-beam epitaxy (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 2764-2766 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: High-power (2.2 W) cw operation has been achieved in a (111)-oriented GaAs/AlGaAs graded-index separate-confinement-heterostructure single-quantum-well laser with the 100-μm wide stripe geometry. High differential quantum efficiency of 81% has been obtained up to ∼1.2 W, and high total power-conversion efficiency of 46% has been achieved at 1.5 W.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.341624
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  • 3
    Electronic Resource
    Electronic Resource
    Structural and optical investigations of high quality InGaAs/InAlAs short period superlattices grown on an InGaAs quasisubstrate (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 5915-5920 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Unstrained InGaAs (4.5 nm)/InAlAs (1.0 nm) short-period superlattices grown on a (100) GaAs substrate were studied. To achieve this growth, an In-composition-graded buffer layer and a thick InGaAs buffer layer were adopted. Structural properties were investigated by x-ray diffraction, atomic force microscopy, and a compositional analysis by the thickness fringe method. X-ray diffraction patterns showed clear periodicity in the superlattices and atomic force spectroscopy images showed cross-hatch morphology for the main ridge along the (011¯) direction. Clear thickness fringes in the bright-field electron microscope images for the superlattice region and ambiguous fringes for the graded buffer layer indicate that misfit dislocation due to lattice mismatch concentrates in the graded buffer and a high-quality superlattice is successfully grown in spite of the large lattice mismatch between the superlattice and the substrate. Optical characteristics measured by photocurrent spectroscopy reveal a clear Wannier–Stark localization effect at room temperature. The experimental absorption energies agree well with calculated values by a transfer matrix method using parameters for bulk InGaAs and InAlAs. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363587
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  • 4
    Electronic Resource
    Electronic Resource
    Picosecond time-resolved absorption spectrometer using a streak camera (1991)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 62 (1991), S. 1415-1419 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: A picosecond time-resolved absorption spectrometer is described. The apparatus consisting of a probe light source, a polychromator, and a streak camera enables us to observe time-resolved absorption spectra in the range from picoseconds to several nanoseconds, with 50 ps time resolution. The probe light has the properties of a wide range continuum spectrum from UV to near IR and is of several tens of nanoseconds in duration. Using this apparatus, with only a single laser shot, we can observe transient absorption both temporal and spectral simultaneously. This apparatus is useful for studying the primary process of photochemical dynamics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1142460
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  • 5
    Electronic Resource
    Electronic Resource
    Carrier transport in GaAs/AlAs type-II superlattices under electric field: Switch from X–X to Γ–Γ transfer (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 1866-1868 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A switch in carrier transport from X–X to Γ–X–Γ is found in a GaAs/AlAs type-II superlattice under an electric field. This phenomenon is caused by an X–Γ transfer, as demonstrated by the photoluminescence, photocurrent response, and current–voltage characteristics. Under a high electric field, most of the electrons flow through the Γ path even in type-II superlattices. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126194
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  • 6
    Electronic Resource
    Electronic Resource
    Rapid collapse of Wannier–Stark localization caused by space charge electric field screening in short-period superlattices (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 5094-5105 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A rapid optical absorption change is observed in a GaAs/AlAs short-period superlattice having Wannier–Stark localization. This phenomenon is clearly explained by a rapid collapse of Wannier–Stark localization due to electric field screening by photogenerated space charges. The screening causes a positive feedback loop between restoration of the blue-shifted wavelength of the absorption band-edge towards the red and an increase in optical absorption, which causes an additional field screening. The experimental bias voltage dependence of the intensity of photoluminescence and photocurrent under high optical excitation, agree well with a model applying Fowler–Nordheim tunneling at the heterointerface cladding layer. It is concluded that the space charges are stopped near the cladding layer and that the superlattice region is almost fully screened to near the flat-band bias condition. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363489
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  • 7
    Electronic Resource
    Electronic Resource
    Wannier–Stark localization in strained barrier GaAs/InXAl1−XAs superlattices (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 2285-2290 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the observation of the Wannier–Stark localization effect in short period GaAs/ InXAl1−XAs superlattices with strained barriers. The superlattices, each of which is contained in the intrinsic region of a p-i-n diode structure, consist of GaAs (3.0 nm) wells and strained shallow InXAl1−XAs (0.9 nm) barriers (X=0, 0.1, 0.2, and 0.3) grown on GaAs by molecular beam epitaxy. In spite of the use of strained barriers, the Wannier–Stark localization effect is clearly observed for all samples at room temperature. Even the superlattice sample with the highest In content of X=0.3 exhibits distinct photocurrent spectra showing several peaks associated with Wannier–Stark ladder transitions as well as Franz–Keldysh oscillations. It is found that the transition intensities are consistent with theoretically calculated oscillator strengths based on the simplified tight-binding model. By increasing the In content X, the miniband width increases and the absorption peak energy due to the zeroth order ladder (e1-hh1 and e1-lh1) transitions decreases because of the reduced barrier height. The transition energies are consistently explained by taking modulation effects into account on the valence subbands due to the compressively strained barriers. The above results show that the use of a large strain effect on the barriers is possible in Wannier–Stark localization effect type devices. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363057
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  • 8
    Electronic Resource
    Electronic Resource
    Avalanche breakdown mechanism originating from Γ–X–Γ transfer in GaAs/AlAs superlattices (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 2827-2829 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: An avalanche breakdown mechanism in GaAs/AlAs type-I superlattices is demonstrated. This mechanism shows its power at a bias voltage where both of the following two conditions are met. One is electron transfer from the Γ ground state to the X ground state (Γ1-X1), and the other is the escape of electrons from the X1 state to the second Γ state (X1-Γ2). Under both conditions, because the AlAs barriers become transparent for electron transport due to the Γ1-X1-Γ2 path, the drift speed (i.e., the acceleration of electrons) grows, and then the superlattice shows the phenomenon of avalanche breakdown. From our experimental results for various GaAs/AlAs superlattices, it is thought that such avalanche breakdown frequently occurs when type-I GaAs/AlAs superlattices have thick barrier widths. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120148
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  • 9
    Electronic Resource
    Electronic Resource
    Influence of Γ-X resonances on Γ1 ground state electron occupation in type-I GaAs/AlAs superlattice (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 1581-1583 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The influence of Γ-X resonances on Γ1 ground state electron occupation in type-I direct-gap GaAs/AlAs superlattices was studied under an applied electric field. Photoluminescence and photocurrent-voltage characteristics showed anomalous behaviors at corresponding Γ-X resonance voltages. The experimental results demonstrate that Γ1-Xn transfer degrades the sweep-out of carriers, while X1-Γ2 transfer promotes it. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118637
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  • 10
    Electronic Resource
    Electronic Resource
    Delayed photocurrent affected by Γ-X resonance in GaAs/AlAs type-I short-period superlattices (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 3292-3294 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Delayed photocurrents were observed in GaAs/AlAs type-I short-period superlattices by measuring time-resolved photoresponses under ultrashort optical pulse excitation. According to the envelope function calculations, the X1 state in AlAs barriers resonates with the Γ2 state in the adjacent GaAs wells at a bias voltage where the delayed photocurrents were conspicuous. These results strongly suggest that the dynamic carrier transport process is significantly influenced by X1-Γ2 resonance effects in the superlattices. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115224
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