Luminescence anisotropy of ZnO microrods

The local features of light emission from ZnO microrods were studied: it is revealed that ZnO luminescence spectra are significantly influenced by the crystal morphology. It is shown that the near and edge ultraviolet emission occurs primarily from the top (0001) planes of ZnO microrods; while the defect related visible emission was found to occur dominantly from the side facets. The room temperature cathodoluminescence analysis revealed that visible emission consists of a few overlapping peaks, arising due to recombination on common points and surface defects (Zn-i, V-o, V-o(O)/V-o(**) V-o(**) and surface defects.). While at low temperature, only the luminescence due to neutral donor bound exciton ((DX)-X-0) emission is observed. The data obtained suggest that the light emission spectra of ZnO material of diverse morphology cannot be directly compared, although some common spectral features are present. (C) 2012 Elsevier B.V. All rights reserved.