Microstructure of zinc oxide grown by rf magnetron sputtering: Aspect of oxygen vacancy

The diffusion characteristics of oxide ions and microstructures were studied to reveal the relationship between the defect characteristics and their properties such as electrical conductivity. ZnO films were prepared by the rf magnetron sputtering method. The films were grown epiraxially, maintaining the substrate temperature above 400 degreesC. According to scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation, the films have a column at microstructure and sub grain boundaries. The diffusion measurement of oxide ions revealed that the amount of meta stable oxygen defects was more in as-deposited films than in those annealed in air. The meta stable oxygen defects played the role of donors.