All-Inorganic Nanocomposite Enhancing Photomultiplication for Sensitive and Stable Ultraviolet Detection

Abstract

Although photovoltaic ultraviolet (UV) detectors, typically made from silicon, silicon carbide, or gallium nitride, are well developed and have the advantages of simple fabrication and low-power operation, their relatively limited responsivities are unsuitable for practical applications that require ultrahigh sensitivity to weak UV light. On the contrary, the field-effect phototransistors, fabricated via complex processes along with high-voltage operation, can achieve an ultrahigh photoresponse. As a reasonable compromise among high performance, ease of production, and operation, we propose a photomultiplication (PM)-type UV detector based on an inorganic SnO 2 :TiO 2 photoactive layer. Owing to effective trap-assisted band bending of the TiO 2 layer upon UV light, the PM device exhibits a high specific detectivity of 2.3 × 10 13 Jones and a superior external quantum efficiency of 2220% at an extremely low light intensity of 37.5 pW. Hence, this study provides a platform for designing high-sensitivity PM detectors for practical applications.