Si nanohole array (Si NHA)-based type-I heterojunction for filterless self-powered ultraviolet photodetection

Abstract

We report on the fabrication of Si nanoholes array (NHA)/SnO type-I heterostructure through RF magnetron sputtering p-SnO film onto n-Si NHA substrate, using a high-purity Sn target. For the Si NHA with a period of 300 nm, stronger light trapping of UV light is expected. Meanwhile, due to the large valence band offset, the transportation of photogenerated holes in Si-side is impeded. This suppresses the contribution of visible and near-infrared absorption of Si to the photoresponse, resulting in a response dominated by the wide-bandgap SnO film. The device functions well as a self-powered and filterless UV photodetector, showing responsivity of 0.28 A W⁻¹, specific detectivity of 1.10×10¹³ Jones, and a fast response speed (240/190 μs for rise/fall) under 265 nm illumination. The device also exhibits promising potential for anti-interference UV communication.