The effects of growth temperature on structural and emission properties of ZnO nanorod arrays grown by low-temperature metalorganic chemical vapor deposition

One-dimensional ZnO nanorods were grown on sapphire and Si substrates at various temperatures by metalorganic chemical vapor deposition using a gas supply system designed for the growth at reduced temperatures. The ZnO layers grown on the Si substrates showed a higher growth rate and inclined nanorods at lower temperatures, compared to those on the sapphire substrates. This difference was attributed to the large lattice mismatch and less domain matching epitaxy. A higher growth temperature resulted in the formation of high optical quality ZnO nanorods with a high aspect ratio. For ZnO nanorods on Si, photoluminescence revealed excitonic emission with monotonic bandgap shrinkage according to Varshni's law. PACS: 68.37.Lp; 68.55.A; 61.72.Nn; 61.43.Bn