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  • American Institute of Physics (AIP)  (32)
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  • 1
    Electronic Resource
    Electronic Resource
    Structural improvement in sublimation epitaxy of 4H–SiC (2000)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 1407-1411 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The sublimation epitaxy growth process has been studied. The structural quality of the grown layers improves compared with the substrate mainly due to a diminished domain structure misorientation. Optical microscopy shows that the as-grown surfaces are free of typical defects appearing in silicon carbice (SiC) epitaxy, whereas atomic force microcopy measurements show macrosteps. As a possible technique to produce high-quality 4H–SiC, sublimation epitaxy was performed on substrates containing a layer grown by liquid phase epitaxy which is a growth process for closing micropipes in the initial substrate. In spite of the initial surface roughness of the liquid phase epitaxy layer, the surface morphology of the sublimation grown epilayers remained smooth and the structural quality improvement was maintained. This does not occur if the initial surfaces are too rough. A suggestion for roughness reduction is presented. The growth conditions (growth rate ramp up, growth temperature, temperature gradient, source to substrate distance, and substrate surface orientation) leading to the results are presented. A model for the mechanism for structural improvement is outlined and supporting experimental observations are given. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.373831
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  • 2
    Electronic Resource
    Electronic Resource
    Photoluminescence and Zeeman effect in chromium-doped 4H and 6H SiC (1999)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 86 (1999), S. 4348-4353 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Photoluminescence (PL) and Zeeman effect measurements in near-infrared luminescence bands in Cr-doped 4H and 6H SiC are presented. The PL spectrum consists of two no-phonon lines (NPLs) at 1.1583 and 1.1898 eV in 4H SiC and three NPLs at 1.1556, 1.1797, and 1.1886 eV in 6H SiC. The observed Zeeman splittings and temperature dependence studies reveal the spin triplet of the ground state and the orbital doublet structure of the excited state of the Cr-related center. All the triplets have almost isotropic g values close to 2 with trigonal symmetry and small zero-field splitting values D. In contrast, the effective g values of the excited state of the center are very anisotropic with g(parallel) in the range of 0.22–0.64 and g⊥=0 for different NPLs in both polytypes. Based on the Zeeman results, the PL is attributed to the internal transition 1E(D)→3A2(F) within the d shell of a substitutional, neutral chromium (Cr4+) in the 3d2 electronic configuration. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.371368
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  • 3
    Electronic Resource
    Electronic Resource
    Metastable defects in 6H–SiC: experiments and modeling (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 1324-1330 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Using various junction space-charge techniques, annealing, and simulation, a metastable defect in 6H SiC have been characterized. We suggest a configuration coordinate diagram with three configurations, where two of them can only exist when the defect is occupied by one or more electrons. The thermal ionization energies for the different configurations were measured and the thermal barriers for two of the transitions have been determined. It is also shown that the transformation process is governed by electron capturing to the defect. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1427401
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  • 4
    Electronic Resource
    Electronic Resource
    Excitation spectra of nitrogen bound excitons in 4H- and 6H-SiC (2002)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 2028-2032 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report photoluminescence excitation spectra of the nitrogen (N) donor bound excitons (BE) in 4H- and 6H-SiC. The spectra reveal several excited states of the N-BEs. An attempt is made in the article to classify the N-BE states according to a simple shell model. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1431437
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  • 5
    Electronic Resource
    Electronic Resource
    Nitrogen doping concentration as determined by photoluminescence in 4H– and 6H–SiC (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 3504-3508 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Low-temperature photoluminescence (PL) spectroscopy is used for determination of the nitrogen doping concentration in noncompensated 4H– and 6H–SiC by comparing the intensity of nitrogen-bound exciton (BE) lines to that of the free exciton (FE), the latter being used as an internal reference. The results are compared with a previous work performed for the case of 6H–SiC only. A line-fitting procedure with the proper line shapes is used to determine the contribution of the BE and FE lines in the PL spectrum. The ratio of the BE zero-phonon lines (R0 and S0 in 6H, Q0 in 4H) to the FE most intensive phonon replica around 77 meV exhibits very well a direct proportional dependence on the doping as determined by capacitance–voltage (C–V) measurements for both polytypes. The use of fitting procedure which takes into account the real line shapes, the influence of the spectrometer transfer function, and the structure of the PL spectrum in the vicinity of the FE replica allows us determination of the N-doping concentration by PL for doping levels in the region 1014 cm−3–3×1016 cm−3 for 4H– and 1014 cm−3–1017 cm−3 for 6H–SiC. Above these levels the free-exciton related emission is not observable. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363221
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of vapor composition on polytype homogeneity of epitaxial silicon carbide (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 5704-5712 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The silicon to carbon precursor ratio is demonstrated as strongly affecting the spontaneous nucleation of cubic SiC upon the growth of epitaxial layers of 4H and 6H silicon carbide using the chemical vapor deposition (CVD) technique. High C/Si ratios appear to promote the nucleation of cubic SiC. A model of CVD process chemistry that relates the effect to a decrease of SiC surface mobility with an increase of the C/Si ratio is proposed. The resulting increase of supersaturation at the surface terraces promotes the spontaneous nucleation of cubic SiC. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.363622
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  • 7
    Electronic Resource
    Electronic Resource
    Temperature dependence of the minority carrier lifetime in GaAs/AlGaAs double heterostructures (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 4808-4810 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have studied the photoluminescence decay time in a series of high quality GaAs/AlGaAs double heterostructure samples, grown by liquid phase epitaxy, with different p-type doping. We have compared the experimentally observed decay time as a function of temperature from 100 to 700 K, with a complete calculation of the radiative recombination rate, including the temperature dependence of the reabsorption factor. We conclude that the observed decay time is well explained by a dominating radiative recombination up to temperatures of about 500 K. The internal quantum efficiency is hence close to unity. At higher temperatures we observe a deviation from the expected values for the radiative recombination, attributed to a nonradiative recombination channel. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.360740
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  • 8
    Electronic Resource
    Electronic Resource
    Temperature and doping dependence of the photon recycling effect in GaAs/AlGaAs heterostructures (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 4611-4615 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have calculated the effect of photon recycling, as a function of energy, temperature, and doping level in GaAs/AlGaAs double heterostructures. The calculations have been performed numerically using energy-dependent expressions for the absorption, emission, and refractive indices. Our calculations are compared to experiments, and we demonstrate the influence of the photon recycling on the photoluminescence line shape, both peak position and the high energy slope, total intensity, and decay time. The calculations show that the total emitted photoluminescence intensity should weakly increase with increasing temperature, if the internal quantum efficiency is 1. The experimentally observed intensity loss at high temperatures (700 K) is explained as due to a reduction of the internal quantum efficiency. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359426
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of microwave fields on recombination processes in 4H and 6H SiC (1997)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 81 (1997), S. 1929-1932 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of microwave fields on recombination processes, which are responsible for the optical detection of cyclotron resonance (ODCR) in 4H and 6H SiC epitaxial layers, have been investigated. We present experimental evidence indicating that the dominant mechanism of ODCR in SiC, at low temperatures and in a common range of microwave power (〈200 mW), is microwave-induced lattice heating under the cyclotron resonance conditions. The results also show that at low temperatures and low microwave power the dominant scattering mechanism is impurity scattering, while carrier scattering by lattice phonons dominates under high microwave power conditions. © 1997 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.364048
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  • 10
    Electronic Resource
    Electronic Resource
    Dominant recombination center in electron-irradiated 3C SiC (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 3784-3786 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Deep level defects and their role in carrier recombination processes in electron-irradiated 3C SiC have been studied by photoluminescence (PL) and optically detected magnetic resonance (ODMR). An isotropic ODMR spectrum, with a g value of 2.0061±0.0002 and an effective electron spin S=1/2, is observed in irradiated 3C SiC films. From the spectral dependence studies of the ODMR signal, the defect is shown to be a deep level center related to a radiation-induced PL band with a zero-phonon line at 1.121 eV. Due to the competition between different carrier recombination channels, this ODMR spectrum can also be observed as a decrease of any other PL emissions from the sample, indicating its dominant role in recombination processes. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361214
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