The Effect of Tensile Strain on Optical Anisotropy and Exciton of $m$-Plane ZnO

The near band edge emission of the tensile-strained
$m$
-plane ZnO film grown on (112)
$\hbox{LaAlO}_{3} $
substrates shows abnormal low polarization degree (
$\rho = 0.1$
) . The temperature dependency of polarization degree clarifies the origins of different emission peaks. In tensile-strained m-plane ZnO, the [0001] polarized state is upper shifted and is overlapping with the [
$11\overline{2} 0$
] polarized state. This phenomenon causes the abnormal low polarization degree and reveals the effect of strain on the emission anisotropy of
$m$
-plane ZnO.