Formation mechanisms of ZnO nanocrystals embedded in an amorphous Zn2xSi1−xO2 layer due to sputtering and annealing

▶ ZnO nanocrystals embedded in an amorphous Zn2xSi1−xO2 layer inserted between a ZnO thin film and a p-Si (1 0 0) substrate were formed by magnetron sputtering and thermal annealing. High-resolution transmission electron microscopy images showed that ZnO nanocrystals were embedded in the Zn2xSi1−xO2 layer inserted into a ZnO/Si heterostructure. The {011¯0} planes were observed for the ZnO nanocrystals with a [0 0 0 1] orientation direction, and the {011¯1} and the {0 0 0 1} planes were observed for the ZnO nanocrystal with a [21¯1¯0] orientation direction. The formation of ZnO nanocrystals consisting of the most stable {0 0 0 1} and {011¯1} facet planes was attributed to atomic rearrangement of Zn and O atoms to reduce the surface energy during the thermal annealing and the cooling processes.