Polarization switching phenomena in semipolarInxGa1−xN/GaNquantum well active layers

Abstract

We report the observation of optical polarization switching in ${\text{In}}_{x}{\text{Ga}}_{1\ensuremath{-}x}\text{N}/\text{GaN}$ quantum well active layers, using semipolar ${11\overline{2}2}$ planes. When the In composition is less than $\ensuremath{\sim}30%$, the emissions related to the top and second valence bands are polarized along the $[1\overline{1}00]$ and perpendicular $[\overline{1}\overline{1}23]$ directions, respectively, similar to earlier studies. On the contrary, as the In composition increases above 30%, the polarizations switch, indicating a crossover between the two valence bands. Because the polarization degree is less sensitive to the well width, the observed polarization switch is ascribed to the InN deformation potentials.