Study of ZnO film growth by LP-MOCVD using DEZn and N2O as precursors

• Main Authors: Chih-Wei Li, 李治緯
• Other Authors: Yi-Jia Chen
• Format: Others
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/44156881137611763955

碩士 === 國立東華大學 === 材料科學與工程學系 === 101 === In this research, we prepare ZnO thin film by low-pressure metal-organic chemical vapor deposition (LP-MOCVD), using DEZn as zinc precursor and N2O as oxygen precursor. We observed a special structure which has potential for development into a large single crystal of ZnO. At growth temperature 300oC, we consider that the VI-II ratio (RVI/II) varies between top and bottom of a crystal, and the variation increases as the crystal growth progresses. A special structure is developed with the morphology of the top different from that of the bottom of the crystal. This structure is a large spiral crystal covered by dense ZnO nanorods. The nanorods are vertically aligned to the bottom portion of the crystal, and form a bundle of ZnO nanorods, where the bottom portion of the crystal is grown laterally and was originally grown by spiral mechanism. When bundle nanorods nucleate on the spiral crystal, the spiral crystal can maintain the lateral growth mode, the crystal size continuously increasing. Due to the fact that these nanorods are homogeneously nucleate on the same ZnO crystal, these nanorods can integrate together and become one large single crystal after the anneal treatment. From our experiment, we found out that nucleation rate dominates crystal size at 300oC-400oC. By raising the precursor concentration and deposition time, the structure of the crystal with a large spiral crystal at the bottom and nanorods covered on top grows faster and becomes the main morphology of the film.