A comparable study on temperature-dependent photo-luminescence spectra of Mg0.1Zn0.9O alloy films and ZnO nanoflakes

We make a comparison on the photoluminescence (PL) from the Mg0.1Zn0.9O film and ZnO nanoflakes (NFs) over the range of 10-300 K. It is clear that their PL spectra are dominated by the radiative recombination of localized or bound excitons at 10 K. As the temperature increases, these excitons are gradually converted toward free excitons (FX) or annihilate through a thermal dissociation/activation or a non-radiative recombination channel. In addition, it is found that the quenching behavior of integrated PL intensity exhibit two activation energies in the different temperature ranges for the NFs, suggesting that a re-localization of FX might occur during the range of 70-300 K. (C) 2013 Elsevier Ltd. All rights reserved.