Temperature-dependent photoluminescence properties of ZnO/Zn1−xMgxO multilayers grown by pulsed laser deposition

ZnO/Zn0.9Mg0.1O multilayer thin films were deposited on p-Si(1 0 0) substrates using pulsed laser deposition technique at varying substrate temperatures ranging from 300 °C to 700 °C. X-ray diffraction (XRD) studies reveal that the films possess a preferred (0 0 0 2) growth orientation with the intensity gradually increasing with substrate temperature. Temperature-dependent photoluminescence properties were studied in details to investigate the origin of near band edge emission and the quenching mechanism. The band gap at 10 K shows a blue-shift with the increase of substrate temperature, but is found to be higher for the sample grown at 500 °C than that of the 600 °C and 700 °C grown samples at all temperatures above 25 K. It appears that the dominant recombination mechanism changes from donor-bound to localized excitons with the increase in substrate temperature.