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Optical polarization anisotropy of nonpolar InN epilayers
Author(s) -
Wang K.,
Yamaguchi T.,
Takeda A.,
Kimura T.,
Kawashima K.,
Araki T.,
Nanishi Y.
Publication year - 2010
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.200983657
Subject(s) - anisotropy , orthorhombic crystal system , polarization (electrochemistry) , condensed matter physics , perpendicular , materials science , photoluminescence , optics , diffraction , physics , chemistry , geometry , mathematics
Photoluminescence (PL) intensity of both a ‐plane and m ‐plane InN epilayers has been observed to strongly depend on polarization angle. The PL intensity for polarization perpendicular to c ‐axis ( E ⟂ c ) is up to four times as that of polarization parallel to c ‐axis ( E // c ) for a ‐plane InN, and this ratio is up to seven times for m ‐plane InN. The absorption edges of a ‐plane samples for the two polarizations are separated by 19 meV, with ( E // c ) at higher energy side. The PL detected from sample edge also shows such anisotropy. X‐ray diffraction experiments for a series of a ‐plane samples, taking orthorhombic distortion of lattice into account, have shown some samples are compressively strained along growth direction and others have negligible strain. With measured strain, the polarization anisotropy has been analyzed by comparing the experimental results with calculated transition energies and relative oscillator strengths including anisotropic in‐plane strain.