Characterization of AZO/p-Si heterojunction prepared by DC magnetron sputtering

Al-doped ZnO (AZO) film was deposited by direct-current (DC) magnetron sputtering on p-Si (1 0 0) wafer to fabricate Al-doped n-ZnO/p-Si heterojunctions. The microstructural, optical and electrical properties of the AZO film were characterized by XRD, SEM; UV–vis spectrophotometer; four-point probe and Hall effect measurement, respectively. Results show that the AZO film is of good quality. The electrical junction properties were investigated by I–V measurement, which reveals that the heterojunction shows rectifying behavior under a dark condition. The ideality factor and the saturation current of this diode are 20.1 and 1.19×10−4 A, respectively. The value of IF/IR (IF and IR stand for forward and reverse current, respectively) at 5 V is found to be as high as 19.7. It shows fairly good rectifying behavior, indicating formation of a diode between AZO and p-Si. High photocurrent is obtained under a reverse bias when the crystalline quality of AZO film is good enough to transmit light into p-Si.