An investigation on hysteresis process of ZnO film deposition and changes of surface morphology and wettability

摘要

Plasma Optical Emission Spectroscopy was employed to investigate hysteresis process of reactive sputtering with high purity Zn target in the presence of Ar plus O_2 plasma. An optimal working point was obtained through analyzing hysteretic curve in order to deposit high quality ZnO film. Scanning Electron Microscope was used to characterize effects of various O_2 flow rate on surface crystal structure of samples. The SEM results indicate that the structure of ZnO film is strongly dependent on O_2 flow rate at constant pressure and power. Specially, At 1.6 sccm O_2 flow rate, the sample with best crystallite structure has been observed. Energy-dispersive X-ray Spectroscopy also demonstrates the relationship between the chemical compositions of ZnO films and O_2 flow rate. The film to 1.6 sccm O_2 shows the optimal atom ratio of Zn to O and the mass ratio of Zn to O. The water contact angle measurement also shows various O_2 flow rate strongly affects wettability.