Exciton photoluminescence of hexagonal ZnO

Abstract

Photoluminescence spectra of ZnO layers obtained by radical-beam epitaxy have been studied. Photoluminescence of free $B$ and $C$ excitons has been observed. At a high excitation level a band with ${\ensuremath{\lambda}}_{\mathrm{max}}=363.1 \mathrm{nm}$ is observed. It is explained in terms of the proposed photoluminescence polariton mechanism in the ${B}_{n=1}$ exciton spectral region through biexcitons