Self-powered and temperature-tunable infrared-visible photodetector based on a VO2/Si heterojunction

Abstract In this work, a type-III heterojunction based on a pulsed-laser-deposited vanadium dioxide (VO 2 ) and p-type silicon (p-Si) substrate is realized. The device shows a large self-powered and room-temperature photoresponse to IR (950 nm), green (515 nm) and blue (456 nm) LEDs. A short-circuit current ( I sc ) of ∼3 µ A and an open-circuit voltage ( V oc ) of ∼−120 mV are observed under IR LED illumination. The work function data in literature along with the sign of V oc measurement is used to sketch the energy band diagram of the heterojunction. The temperature-dependent I sc properties of the junction, contrary to conventional photodetectors, show an initial rise and then a sharp transition from maximum (3.5 μ A) to almost zero near 337 K, corresponding to a metal–insulator phase transition, paving the way for photodetectors with temperature-tunable photoresponsivity.