Realization and characterization of an ITO/AZO/SiO2/p-Si SIS heterojunction

A novel ITO/AZO/SiO2/p-Si SIS heterojunction has been fabricated by low temperature thermal growth of an ultrathin silicon dioxide and RF sputtering deposition of ITO/AZO double films on a p-Si texturized substrate. The crystalline structure and the optical and electrical properties of the ITO/AZO antireflection films were characterized by X-ray diffraction (XRD), UV-VIS spectrophotometry, and four-point probe measurements, respectively. The results show that the ITO/AZO films are of good quality. The electrical junction properties were investigated by I-V measurement, which reveals that the heterojunction shows strong rectifying behavior under a dark condition. The ideality factor and the saturation current of this diode are 2.3 and 1.075×10−5 A, respectively, and the value of IF/IR (IF and IR stand for forward and reverse current, respectively) at 2 V is found to be as high as 16.55. The junction shows fairly good rectifying behavior, indicating the formation of a diode between AZO and p-Si. High photocurrent is obtained under a reverse bias when the crystalline quality of ITO/AZO double films is good enough to transmit the light into the p-Si.