Raman measurements on nanocolumnar ZnO crystals

Hexagonal zinc oxide nanocolumns have been grown on conducting F-doped SnO2 substrates by galvanostatic electrodeposition. Raman and photoluminescence spectra of the ZnO nanocolunms have been measured in several samples with different size distributions as a function of the annealing temperature. Photoluminescence properties of ZnO nanocolumns are strongly influenced by the crystalline quality of the samples. The dependence of the crystalline quality of the samples on the growth parameters and annealing temperature is discussed. In particular, the Raman spectra of as-grown samples exhibit broad bands that correlate perfectly with the one-phonon density of states obtained from recent ab initio calculations. (c) 2005 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.