The study of rapid thermal annealing on arsenic-doped ZnO for the p-type ZnO formation

Abstract

In this research, we successfully prepared p-type ZnO films by rapid thermal annealing (RTA) of As doped ZnO films deposited by magnetron DC sputtering using target made of ZnO mixed with Zn3As2 powders. From the Hall measurement, the doped ZnO film converted from n-type to p-type after RTA of the films at 1000°C for 30s. But it converted to n-type conduction again for higher annealing temperature. The X-ray diffraction (XRD) data indicates the crystallinity of the doped films is improved by increased RTA temperature. We also found that rapid thermal annealing (RTA) results in As–O bonding shift toward higher binding energy. It is an indication of the formation of AsZn–2VZn defect, which is responsible for p-type behavior. Further higher annealing temperature increases oxygen vacancies that may compensate the p-type behavior. Thus the RTA temperature is so critical to form AsZn–2VZn while not to form oxygen vacancies. This partially explains that the p-type ZnO is difficult to prepare.