Annealing Effects of Ti/Au Contact on n-MgZnO/p-Si Ultraviolet-B Photodetectors

Effects of postannealing on Ti/Au-MgZnO contact and n-MgZnO/p-Si heterojunction ultraviolet-B photodetector's performance are investigated. It is found that the out diffusion of oxygen from MgZnO and its bonding with Ti at the interface have significant influences on the properties of Ti/MgZnO interface and photodetector. The persistent photocurrent observed in the annealed device is attributed to the oxygen vacancies near the interface, consistent with the theoretical calculations. It is revealed that the reaction at metal/MgZnO interface possibly plays a key role and even dominates the MgZnO p-n heterojunction ultraviolet detectors' performances.