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  • 1
    Electronic Resource
    Electronic Resource
    Identification of a nonradiative recombination center in GaAs (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 4449-4451 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the identification of the CuGa acceptor level as a recombination center in GaAs. Using time-resolved photoluminescence (PL) we have studied the recombination of excess charge carriers in metalorganic vapor-phase epitaxy GaAs/AlGaAs double heterostructures. The recombination in one particular set of samples was clearly nonradiative and the trap level derived from our measurements coincides with that of CuGa as seen in the PL spectra. The temperature dependence of the capture coefficients is consistent with a multiphonon process and allows for the determination of the coupling strength for electron and hole capture.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.352184
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  • 2
    Electronic Resource
    Electronic Resource
    Electroabsorption studies on quasi-three-dimensional and quasi-two-dimensional excitons in (Zn,Cd)Se/Zn(S,Se) structures (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 4360-4364 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The electro-optical properties of (Zn,Cd)Se/Zn(S,Se) quantum well structures grown on GaAs substrates have been studied with differential electroabsorption spectroscopy at room temperature and compared to model calculations. (Zn,Cd)Se wells of 20, 10, and 4×5 nm are investigated, corresponding to well widths of four, two, and one times the exciton Bohr radius in this material system, respectively. We observe the quantum confined Stark effect for the 4×5 nm sample and find a Stark shift of 18 meV in the heavy-hole exciton peak for an electric field change from 82 to 175 kV/cm. In contrast, the 10 nm sample shows a rather weak and more Franz–Keldysh-like signal. We show that the 20-nm-thick quantum-well sample behaves like bulk material, i.e., the electro-absorption signal is well described by Franz–Keldysh oscillations. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371370
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  • 3
    Electronic Resource
    Electronic Resource
    Indirect-band-gap transition in strained GaInAs/InP quantum-well structures (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 5067-5071 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using photoluminescence (PL) and time-resolved measurements, the valence-band structure of tensile strained GaInAs quantum wells has been evaluated. From temperature-dependent PL, LO-phonon-assisted transitions at energies of about 32 meV below the band gap transition were observed. In addition, a hundredfold increase in the carrier lifetime of tensile strained quantum wells compared to unstrained layers was measured. Both findings are strong indications that the maximum of the valence band in k space is shifted away from the center of the Brillouin zone in tensile strained quantum wells near a critical composition, where the lowest heavy-hole and light-hole levels cross each other, thus giving rise for indirect optical transitions as predicted by theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.355749
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  • 4
    Electronic Resource
    Electronic Resource
    Dynamics of dual-wavelength emission from a coupled semiconductor microcavity laser (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 70 (1997), S. 2073-2075 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present an experimental demonstration of the dynamics of dual-wavelength emission from a coupled semiconductor microcavity laser after femtosecond optical excitation at 20 K. The coupled microcavity laser is comprised of two λ sized Al0.2Ga0.8As/Al0.5Ga0.5As cavities, separated by a common mirror. The bottom cavity contains three 10 nm thick GaAs quantum wells (QWs) whereas the top cavity contains three 16 nm thick GaAs QWs. Time-resolved measurements of the stimulated emission show pulses as short as 4.8 ps (10 ps) and peak delays as short as 13 ps (16 ps) for the shorter (longer) emission wavelength. Fast pulse fall times of 1 ps are observed for the pulses of the shorter emission wavelength which can be explained by the simultaneous interaction of the two photon modes with both gain regions of the two types of QWs. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.118955
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  • 5
    Electronic Resource
    Electronic Resource
    Emission dynamics of In0.2Ga0.8As/GaAs λ and 2λ microcavity lasers (1996)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 156-158 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We study the emission dynamics of two In0.2Ga0.8As/GaAs microcavity lasers after femtosecond optical excitation at 20 K. The pulse widths and the peak delays of λ and a 2λ cavity are compared. Pulses as short as 3.3 ps (9.5 ps) and peak delays as short as 8.2 ps (16.5 ps) are obtained with the 2λ cavity (λ cavity). The pulse widths and peak delays are well described by a model based on a rate equation analysis for carrier and photon densities; in particular, the better high speed characteristics of the 2λ cavity compared to the λ cavity are well reproduced. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.116132
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  • 6
    Electronic Resource
    Electronic Resource
    Picosecond lasing dynamics of gain-switched (Zn,Cd)Se/Zn(S,Se)/(Zn,Mg)(S,Se) quantum well lasers (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 82 (1997), S. 548-551 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present the temporal and spectral evolution of stimulated emission from (Zn,Cd)Se/Zn(S,Se)/(Zn,Mg)(S,Se) multiple quantum well lasers at 2 K after picosecond optical excitation. For pumping well above the threshold, ultrahigh-frequency oscillations of up to 100 GHz are observed. These oscillations are generated by a multimode emission through mode beating caused by the coherent superposition of longitudinal ground modes and higher lateral modes. The modelling of the experimental results shows that the modes are coupled to some extent. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.365613
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  • 7
    Electronic Resource
    Electronic Resource
    Transient pulse response of In0.2Ga0.8As/GaAs microcavity lasers (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 1599-1601 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We investigate the transient emission of two In0.2Ga0.8As/GaAs microcavity laser samples with one and three quantum wells at 20 K following femtosecond optical excitation. The stimulated emission time is faster when the cavity resonance is tuned to shorter wavelengths within the gain spectrum of the quantum well. A larger number of quantum wells makes the dynamical response faster also. The narrowest pulse width observed is 6.8 ps, and the shortest rise time is 1 ps. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113864
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  • 8
    Electronic Resource
    Electronic Resource
    Time-bandwidth product of gain-switched In0.2Ga0.8As/GaAs microcavity lasers (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1363-1365 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present the temporal and spectral evolution of stimulated emission from In0.2Ga0.8As/GaAs microcavity laser samples at 20 K after femtosecond optical excitation. Both, linewidth and chirp become smaller when the cavity resonance is at shorter wavelengths within the gain spectrum of the quantum well: The linewidth is reduced from Δλ=0.41 nm at 923 nm, where the threshold is lowest, to Δλ=0.26 nm at 884 nm. Comparison with a phenomenological model yields linewidth enhancement factors α of 2 and 5 for emission wavelengths of 884 and 925 nm, respectively. A time-bandwidth product of 0.68 is obtained at the shorter wavelength. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.115534
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  • 9
    Electronic Resource
    Electronic Resource
    Quantum confined Stark effect of II-VI heterostructures suitable as modulators in the blue–green spectral region (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 3320-3322 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present a systematic and quantitative investigation of the quantum confined Stark effect in (Zn, Cd)Se/Zn(S,Se) quantum well structures at room temperature. For this purpose, differential transmission spectroscopy is performed on two samples with different thicknesses of the active layers (4×5 nm and 10 nm) and compared to model calculations. We observe a Stark shift of 18 meV in the heavy-hole exciton peak for an electric-field change from 82 to 175 kV/cm for the 4×5 nm sample. In contrast, the 10 nm sample shows a rather weak and more Franz–Keldysh-like signal. Furthermore, we have analyzed the spectral behavior of the linewidth enhancement factor αH. Values between 5.1 and 0.2 are found at the energy of absolute maximum of the absorption change for the 4×5 nm sample. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.121637
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  • 10
    Electronic Resource
    Electronic Resource
    Influence of the barrier height on carrier recombination and transparency density in GaN-based laser structures (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 755-757 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using temperature-dependent and gain measurements, we have examined the laser threshold density of (In,Ga)N/GaN/(Al,Ga)N laser structures with various well widths and different In contents in the active layer. Thermal activation energies, obtained by temperature-dependent photoluminescence measurements at low excitation densities, yield information on the nonradiative recombination channels and demonstrate the existence of two different activation processes. One of them may be related to thermal activation of localized carriers into quasifree states and subsequent nonradiative recombination. The other is attributed to thermal emission of carriers into the barriers. The influence of the barrier height is also reflected by the dependence of the threshold densities required on the temperature. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1434305
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