On optical polarization and charge carrier statistics of nonpolar InGaN quantum wells
L. Schade1, T. Wernicke2, J. Rass2,3, S. Ploch2, M. Weyers3, M. Kneissl2,3, and U.T. Schwarz1,4
Published in:
phys. stat. sol. (b), vol. 253, no. 1, pp. 145-157 (2016).
Abstract:
Optical polarization is a fundamental property of light emission from m-plane InGaN quantum wells. It is a result of band structure, anisotropic strain, the degree of polarization depending on thermal occupation, and band-filling of valence subbands. We analyze the optical-polarized light of nonpolar samples at low and at room temperature over a wide range of excitation density. We observe that the measured energy separation and linewidth of the orthogonally polarized emission depend on carrier density, too. A consistent explanation of these effects is possible in the context of Fermi-Dirac statistics for a degenerate carrier density n > 1017 cm-3 and inhomogeneously broadened density of states. In addition, pulsed electroluminescence experiments were performed to validate our conclusions for optoelectronic devices based on nonpolar InGaN quantum wells.
1 Department of Microsystems Engineering (IMTEK), University of Freiburg, Fahnenbergplatz, 79085 Freiburg im Breisgau, Germany
2 Institute of Solid State Physics, Technische Universitaet Berlin, 10623 Berlin, Germany
3 Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany
4 Institute of Physics, Technische Universitaet Chemnitz, Reichenhainer Str. 70, 09126 Chemnitz, Germany
Keywords:
band structure, efficiency droop, InGaN, nonpolar GaN, polarization.
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