Optical gain for wurtzite GaN with anisotropic strain in c plane

We calculated band structures of (<1(1)over bar 00>)-oriented GaN with various strains. We found that introducing anisotropic strain in the c plane separates heavy hole and light hole bands, We also found that a tensile strain in the (<1(1)over bar 00>) plane makes the light hole band topmost. These two effects result in a reduction in the density of states at the valence band edge. In this way, we can significantly reduce the transparent carrier density to generate gain.