The contribution of quantum confinement to optical anisotropy of a-plane Cd0.06Zn0.94O/ZnO quantum wells

We investigated quantum size effects on polarized photoluminescence (PL) from a-plane Cd0.06Zn0.94O/ZnO quantum wells (QWs) with different well widths (L-W). The degree of polarized PL at 300K increased with a narrowing of L-W, which obeyed the polarization selection rule based on a Boltzmann-like distribution. Furthermore, the narrowing of L-W enhanced the anisotropic lattice distortions in well layers along the growing direction, which resulted in an increase of energy separation between the two topmost valence band levels. The effect of quantum confinement on polarized PL of QWs was accompanied by a change of structural symmetry of the well layers. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4707384]