Effect of post-thermal annealing on properties of ZnO thin film grown on c-Al2O3by metal-organic chemical vapor deposition

In this paper, high-quality ZnO film was grown by metal-organic chemical vapor deposition. Post-thermal annealing was performed on ZnO film in vacuum and oxygen condition. We could find only the X-ray diffraction pattern of (0 0 2) ZnO film indicating strong c-oriented growth. The quality of ZnO film was improved by thermal annealing in vacuum as confirmed by XRD and photoluminescence measurement. Raman scattering on as-grown ZnO film indicated that the quality of ZnO film was improved by thermal annealing in oxygen. The intensity of deep-level emission increased much after annealing in oxygen, while it nearly did not change after annealing in vacuum. We believed that the deep-level emission was related to zinc vacancy. The resistivity increased from 2.4 to 1100Omegacm after thermal annealing in oxygen. (C) 2003 Elsevier Science B.V. All rights reserved.