The polarization dependent photoluminescence at low temperatures of strained semipolar and nonpolar InGaN quantum wells was studied as a function of the emission wavelength. We found for semipolar QWs that the maximum of the spectral resolved optical polarization is either red- or blue-shifted with respect to the maximum of the emission.
In contrast, the nonpolar emission exhibits no clear maximum. We assign all effects to an inhomogeneous broad- ening of the emission caused by indium fluctuations and explain this behavior here in the light of the optical polarization switching. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)