Growth of zinc oxide thin films and nanostructures by wet oxidation

Zn films and Zn-ZnO nanocomposite films were deposited onto glass substrates by magnetron sputtering. Wet oxidation was then used to grow ZnO films and nanostructures from these Zn-based precursor films. Morphological observations clearly showed that ZnO nanowhiskers, nanorods, nanowires, and nanobelts could thermally grow on the precursor surfaces. While, highly porous ZnO films could be prepared by oxidation of Zn-ZnO nanocomposite films in wet atmospheres at elevated temperatures. Optical properties of these ZnO films were also characterized at room temperature by photoluminescence measurements with an Ar+ laser excitation. In general, a strong and predominant ultraviolet emission could be observed on the ZnO films grown from the pure Zn films, while tunable color emissions (green or red) accompanying with a largely suppressed ultraviolet emission could be realized on samples grown from Zn-ZnO nanocomposite films. Based on the structural and optical characterizations, the growth mechanisms and luminescence properties of these nanostructured ZnO films were briefly discussed.