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  • 1
    Electronic Resource
    Electronic Resource
    Decay of stimulated and spontaneous emission in highly excited homoepitaxial GaN (2001)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 3776-3778 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The high-density effects in the recombination of electron–hole plasma in photoexcited homoepitaxial GaN epilayers were studied by means of transient photoluminescence at room temperature. Owing to the "backward" and "lateral" photoluminescence measurement geometries employed, the influence of stimulated transitions on the decay of degenerate nonthermalized plasma was revealed. The lateral stimulated emission was demonstrated to cause a remarkable increase in the recombination rate on the early stage of the luminescence transient. A delayed enhancement of the stimulated emission due to the cooling of plasma from the initial temperature of 1100 K was observed. After completion of the thermalization process and exhaustion of the stimulated emission, the spontaneous-luminescence decay exhibited an exponential slope that relates to the nonradiative recombination of the carriers. The homoepitaxially grown GaN layer featured a luminescence decay time of 445 ps that implies a room-temperature free-carrier lifetime of 890 ps (considered to be extremely high for undoped hexagonal GaN). © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1378802
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  • 2
    Electronic Resource
    Electronic Resource
    Dynamic behavior of hot-electron–hole plasma in highly excited GaN epilayers (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 76 (2000), S. 2388-2390 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The room-temperature spontaneous luminescence of electron–hole plasma was investigated in GaN epilayers under extremely high quasi-steady-state photoexcitation. The photoluminescence spectra were measured for excitation power densities up to 200 MW/cm2 both under quasiresonant and off-resonant excitation conditions. High carrier temperatures up to 1000 K were observed under off-resonant excitation. A nonmonotonous dependence of the luminescence band peak position Ep on the excitation power density was observed. We attribute this nonmonotonous behavior of Ep to two competing mechanisms: (i) band-gap shrinkage due to carrier screening effects (redshift); and (ii) nonequilibrium carrier heating (blueshift). The obtained results are in a good agreement with finite-temperature theory of the band-gap renormalization. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.126355
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  • 3
    Electronic Resource
    Electronic Resource
    Optical bandgap formation in AlInGaN alloys (2000)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 2136-2138 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report on the spectral dynamics of the reflectivity, site-selectively excited photoluminescence, photoluminescence excitation, and time-resolved luminescence in quaternary AlInGaN epitaxial layers grown on GaN templates. The incorporation of a few percents of In into AlGaN causes significant smoothening of the band-bottom potential profile in AlInGaN layers owing to improved crystal quality. An abrupt optical bandgap indicates that a nearly lattice-matched AlInGaN/GaN heterostructure with large energy band offsets can be grown for high-efficiency light-emitting devices. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1314288
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  • 4
    Electronic Resource
    Electronic Resource
    Nonradiative capture of hot photoelectrons by multiphonon emission in highly excited CdS crystals (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 1095-1097 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Luminescence kinetics of nonthermalized electron-hole plasma in highly excited CdS crystals with different concentration of native defects has been studied at T=298 K. The shape of the kinetics indicated an enhancement of the plasma nonradiative recombination with increased carrier effective temperature. The experimental results are in good agreement with a model of thermal activation of nonradiative capture by multiphonon emission in centers with the barrier energy of W=110 meV. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.114972
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  • 5
    Electronic Resource
    Electronic Resource
    Characterization of nonradiative traps by hot electron–hole plasma luminescence dynamics in polar semiconductors (1998)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 72 (1998), S. 241-243 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Luminescence intensity dependence on excitation intensity has been studied at quasi-steady-state conditions in CdS and CdSe crystals at T=294 K and interpreted, with heating of photoelectrons taken into account. The shape of the dependence indicates a reduction of carrier density due to increased effective temperature. A method for estimating the height of the barrier for centers governing the thermally activated nonradiative capture by multiphonon emission is proposed. The barrier heights of 140 and 170 meV in CdS and CdSe, respectively, have been estimated. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120697
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  • 6
    Electronic Resource
    Electronic Resource
    Nonradiative recombination of hot photoelectrons in CdS nanocrystals embedded in glass (1997)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 71 (1997), S. 2502-2504 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Transient luminescence spectra are investigated in highly photoexcited CdS nanocrystals (average radii 5.4–100 nm) embedded in glass. Luminescence-intensity kinetics exhibits distortion attributed to carrier-temperature-activated nonradiative recombination due to multiphonon emission. The distortion enhances with reduced crystallite size indicating that the photomodified semiconductor-glass interface originates deep traps with localization barrier of 130 meV. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.120101
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  • 7
    Electronic Resource
    Electronic Resource
    Heating of photogenerated electrons and holes in highly excited GaN epilayers (1999)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 2277-2279 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Heating of nonequilibrium carriers under intense off-resonant photogeneration was investigated in GaN epilayers at T=80 K. We determined that under these extreme conditions hot electrons and hot holes exhibit different patterns of energy dissipation. A good agreement between the experimental data and modeling results was achieved by assuming negligible efficiency of optical-phonon emission by holes. This implies that hot holes, contrary to hot electrons, are unable to establish a smooth distribution function above the threshold of optical phonon emission. We attribute this effect to a large hole mass, strong carrier–phonon coupling, and large optical-phonon energies in GaN. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.124989
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  • 8
    Electronic Resource
    Electronic Resource
    Optimization of white polychromatic semiconductor lamps (2002)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 234-236 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A stochastic method of optimization of a white-light source that relies on additive color mixing of the emissions from colored light-emitting diodes (LEDs) was developed. The method allows for finding the optimal wavelengths of LEDs in order to obtain the best possible trade off between luminous efficacy and the general color rendering index (CRI) of the white source for an arbitrary number of primary LEDs. Optimal solid-state lamps composed of two, three, four, and five different LEDs were analyzed. We show that a dichromatic LED lamp can only provide high efficacy with a general CRI close to zero, whereas trichromatic and quadrichromatic lamps are able to cover the entire range of reasonable general CRI values. The optimization of quintichromatic LED lamps and lamps with a higher number of primary color LEDs yields a negligible benefit in improving CRI but provides for quasicontinuous spectra that might be required for special lighting needs. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1432107
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  • 9
    Electronic Resource
    Electronic Resource
    Surface recombination of nonequilibrium electron-hole plasma in laser-modified semiconductor-doped glasses
    Amsterdam : Elsevier
    Solid State Communications 87 (1993), S. 577-580 
    Details
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1098(93)90600-R
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  • 10
    Electronic Resource
    Electronic Resource
    Exciton system heating in ZnSe single crystals under laser excitation
    Amsterdam : Elsevier
    Solid State Communications 44 (1982), S. 955-957 
    Details
    ISSN: 0038-1098
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0038-1098(82)90312-X
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