ZnO nanocrystals were formed on Si substrates using spin coating and thermal annealing. X-ray diffraction patterns showed that the intensity of the ZnO (0002) peak corresponding to the ZnO [0001] nanocrystals increased with an increase in annealing temperature up to 700 οC, indicative of the improvement of the crystallinity of the ZnO nanocrystals. The photoluminescence spectra at 13 K for ZnO nanocrystals formed on the Si substrates showed that the strong exciton peak related to the near-band-edge emission was shifted to a lower energy with increasing annealing temperature resulting from the increase in the size of the ZnO nanocrystals.

Keywords: Thermal annealing, ZnO nanocrystal, Surface property, Structural property, Optical property.