Characterization of the quality of ZnO thin films using reflective second harmonic generation

A polar mirror symmetrical contribution originated from the arrangement of grain boundaries existing in the ZnO film is detected by reflective second harmonic generation pattern. The ordering of ZnO grain boundary is dependent on the kinetic energy of deposited atoms and affects the quality of ZnO films. The net direction of the grain boundary in ZnO film trends toward the [1- 10] direction of Si(111) to reach the minimum grain energy for better quality ZnO film. The polar structure of the mirrorlike boundaries under the optically macroscopic viewpoint presents a correlation with film quality.