Well‐arrayed ZnO nanostructures formed by multi‐annealing processes at low temperature

A novel process of multi‐annealing was proposed for forming well‐arrayed ZnO nanostructures on as‐deposited ZnO thin films that were prepared on quartz glass using a radio frequency (rf) magnetron sputtering at low temperature. It was found that the formation and morphology of ZnO nanostructures were strongly dependent on the reducing gas annealing processes. Oxygen ambient annealing between two reducing annealing processes had the effect of introducing more oxygen into the ZnO thin film, as well as improving the crystallinity of the ZnO nanostructures. An intense photoluminescence peak centered at 504 nm was observed in the well‐arrayed ZnO nanostructures, due to the large amount of oxygen vacancies which existed on the larger surface area of ZnO nanostructures formed after the multi‐annealing processes at a low temperature of 430 °C. These results show that multi‐annealing processes are very effective in forming well‐arrayed and controllable ZnO nanostructures (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)