In-plane anisotropic photoluminescence of C-plane GaN under asymmetric biaxial strain

The effects of anisotropic strain on wurtzite GaN valence subbands are investigated both theoretically and experimentally. k.p perturbation theory reveals that the in-plane asymmetric strain not only affects the transition energies, but also determines the polarization properties, which is analyzed to be the essential cause of the optical anisotropy. Considerable in-plane anisotropy of strained C-plane GaN in polarized photoluminescence is reported. The experimental result in good agreement with theoretical study directly proves the strain effects on the transitions polarization states. The fine accordance of observed and simulated photoluminescence dependences on strain asymmetry degree demonstrates a primary realization of strain controlled optical anisotropy, and such modulation indicates the great potential of utilizing GaN-based semiconductors in polarization-sensitive optoelectronics. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3157132]