Photoluminescence of ZnO layers grown on opals by chemical deposition from zinc nitrate solution

Abstract

The emission from ZnO layers grown on the surface of bulk opals using chemical deposition is studied under excitation by the 351.1 nm line of an Ar+ laser at different excitation power densities and temperatures. The emission spectrum exhibits narrow photoluminescence (PL) bands associated with the recombination of bound and free excitons as well a relatively broad band around 3.31 eV. The width of the excitonic lines (2–3 meV) along with their energy position are indicative of the high quality and strain-free state of the layer. The origin of the 3.31 eV PL band is discussed in connection with its dependence upon the excitation power density and temperature.