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Strain effect on polarized optical properties of c ‐plane GaN and m ‐plane GaN
Author(s) -
Tao Renchun,
Yu Tongjun,
Jia Chuanyu,
Chen Zhizhong,
Qin Zhixin,
Zhang Guoyi
Publication year - 2009
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.200880404
Subject(s) - valence (chemistry) , oscillator strength , materials science , condensed matter physics , polarization (electrochemistry) , hamiltonian (control theory) , atomic physics , molecular physics , chemistry , physics , quantum mechanics , spectral line , organic chemistry , mathematical optimization , mathematics
The polarized optical property of c ‐plane and m ‐plane GaN with varying strain was discussed by analyzing the changes of relative oscillator strength (ROS) of the three transitions related to the top three valence bands. The ROS was calculated by applying the effective‐mass Hamiltonian based on k · p perturbation theory. For c ‐plane GaN, it was found that ROS of | X 〉 state and | Y 〉 state were superposed with each other. Especially, they increased with compressive strain, while that of | Z 〉 decreased in the second band. For m ‐plane GaN under compressive strain, the first three bands were dominated by | X 〉, | Z 〉 and | Y 〉 states, respectively, which led to nearly linearly‐polarized light emissions. With compressive strain, the ROS of | X 〉 state increased more rapidly than | Z 〉 state in the topmost valence band. As a result, TE mode emissions from both c ‐plane and m ‐plane GaN increased more rapidly than TM mode emission with compressive strain, leading to larger polarization degree. Experimental results of luminescences from InGaN/GaN quantum wells showed good coincidence with our theoretical calculations. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)