Nucleation and growth of ZnO films on Si substrates by LP-MOCVD

• The nucleation and evolution mechanisms of ZnO on Si(1 1 1) were studied in details.
• The control of ZnO nucleation was realized by modifying temperature and time.
• Morphology and crystallinity of ZnO nanorods were improved by changing nucleation.

ZnO was grown on Si (1 1 1) by low-pressure metal–organic chemical vapor deposition. The nucleation and evolution of ZnO thin films were investigated by varying growth temperature and growth time during the nucleation process. It is found that nucleation temperature and time play a key role on the nucleation process. With the increase of nucleation temperature, the size of ZnO nuclei and the spacing between nucleation sites increases. And as the nucleation time increases, the size of ZnO nucleation islands (NIs) increases and the density decreases due to the coalescence of ZnO nuclei. The density and size of initial ZnO NIs have intensely affected the growth model and quality of ZnO epitaxial layers. In addition, the crystalline quality of ZnO thin films was improved by decreasing nucleation temperature and increasing nucleation time.