Abstract
A new method was developed to fabricate high-quality ZnO nanopillars with good uniformity using atomic layer deposition (ALD). The ZnO island seeds were prepared on the (0001) sapphire by the initial 5∼20 ALD cycles at 180°C and then heat-treated at 900°C for 1 h. Afterwards, the ALD growth of ZnO at a temperature as high as 300°C proceeded preferentially on the ZnO island seeds over the sapphire substrate, leading to the formation of ZnO nanopillars. The average diameter and height of the nanopillars are about 60 nm and 50 nm, which can be effectively controlled by the numbers of initial ALD cycles and the following high-temperature ALD cycles, respectively. The ZnO nanopillars have high crystallinity with the [0001] orientation, and exhibit a significant ultraviolet luminescence at room temperature.
