Photoresponse characteristics of n-ZnO/p-Si heterojunction photodiodes

Abstract

Several n-ZnO/p-Si photodiodes were fabricated using rf-sputter deposition with various Ar/O 2 ratios at 480°C. The I-V measurements performed under continuous illumination on the photodiodes exhibited that a high responsivity of 0.286 A/W could be obtained from the photodiode prepared at an appropriate Ar/O 2 ratio of 6:1. The same diode also showed the least dark current leakage while the diode prepared at the high O 2 partial pressure (Ar/O 2=2:1) revealed the largest. Temporal response was measured up to 35 ns from the best n-ZnO/p-Si diodes with the least current leakage and high responsivity in measurements at the high modulation frequency of 1.5 MHz.