ZnO Nanostructures Prepared on LiAlO2 Substrates by Chemical Vapor Deposition

A two-step process of chemical vapor deposition for growing ZnO nanostructures on gamma-LiAlO2 (100) substrate was proposed. By taking advantage of the dual orientation characteristic of the substrate, scattered islands with a {10-10} azimuth orientation were first grown at 650oC to serve as a mask followed by a second-step process at relatively low temperatures of 450-500oC to grow {0001} oriented nanostructures. Two examples were given in this paper. Nanorods of 50-200 nm in size were prepared at a high growing pressure of 200 torr, and nanocones were obtained at 50 torr. The density of the nanostructures can be controlled by the growing time of the first-step process. Both nanostructures were free from threading dislocations and showed good luminescence characteristics.