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Polarization anisotropy in nonpolar oriented GaN films studied by polarized photoreflectance spectroscopy
Author(s) -
Behn Udo,
Misra Pranob,
Grahn Holger T.,
Imer Bilge,
Nakamura Shuji,
DenBaars Steven P.,
Speck James S.
Publication year - 2007
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200673539
Subject(s) - anisotropy , polarization (electrochemistry) , spectroscopy , materials science , condensed matter physics , electronic band structure , band gap , chemistry , optoelectronics , optics , physics , quantum mechanics
Abstract We have used polarized photoreflectance spectroscopy to study the electronic‐band‐structure modification of GaN films grown along different nonpolar orientations due to biaxial, anisotropic in‐plane strain. For nonpolar oriented films, the c ‐axis of GaN lies in the film plane. An unstrained, high‐quality C ‐plane GaN film is used to estimate the difference in the band gap energies between 10 K and room temperature. We use the crystal‐field and spin–orbit splitting energies and the deformation potential D 5 determined at low temperatures to calculate the transition energies and the polarization properties of nonpolar oriented films at room temperature using the k · p perturbation approach. The calculated transition energies and oscillator strengths are then compared to the experimentally obtained values. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)