Highly ordered ZnO nanostructure arrays:Preparation and light-emitting diode application

In this paper, ordered arrays of various ZnO nanostructures were fabricated on both Si and p-GaN substrates via a hydrothermal process by the self-assembled nanosphere lithography (NSL). The morphology and orientation evolution of ZnO nanostructures were well-monitored by varying seed-layer-thickness, solution concentration, and underlying substrate. On this basis, the heterojunction light emitting diode (LED) based on the highly oriented ZnO nanocone array on the p-GaN substrate was fabricated and studied in detail. It is found that the ZnO nanostructure-based LED exhibits a much stronger ultraviolet (UV) emission peaked at 388nm compared with its counterparts based on ZnO film, which is attributed to the low density of interfacial defects, improved carrier injection efficiency through the nano-sized junction, and excellent waveguiding property of the ZnO nanostructure array.