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

摘要

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 Zn_3As_2 powders. From the Hall measurement, the doped ZnO film converted from n-type to p-type after RTA of the films at 1000℃ for 30 s. 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-0 bonding shift toward higher binding energy. It is an indication of the formation of As_(Zn)-2V_(Zn) 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 As_(Zn)-2V_(Zn) while not to form oxygen vacancies. This partially explains that the p-type ZnO is difficult to prepare.