High-performance MoO x /n-Si heterojunction NIR photodetector with aluminum oxide as a tunneling passivation interlayer

Abstract The most effective and potential approach to improve the performance of heterojunction photodetectors is to obtain favorable interfacial passivation by adding an insertion layer. In this paper, MoO x /Al 2 O 3 /n-Si heterojunction photodetectors with excellent photocurrents, responsivity and detectivity were fabricated, in which alumina acts as a tunneling passivation layer. By optimizing the post-annealing treatment temperature of the MoO x and the thickness of the ultra-thin Al 2 O 3 , the photodetector achieved a ratio of photocurrent to dark current of 3.1 × 10 5 , a photoresponsivity of 7.11 A W −1 (@980 nm) and a detective of 9.85 × 10 12 Jones at −5 V bias. Besides, a self-driven response of 0.17 A W −1 and a high photocurrent/dark current ratio of 2.07 × 10 4 were obtained. The result demonstrated that optimizing the interface of heterojunctions is a promising way to obtain a heterojunction photodetector with high-performance.