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

In this work, a type-III heterojunction based on a pulsed-laser-deposited vanadium dioxide (VO2) 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 (Isc) of ∼3 µA and an open-circuit voltage (Voc) of ∼−120 mV are observed under IR LED illumination. The work function data in literature along with the sign of Voc measurement is used to sketch the energy band diagram of the heterojunction. The temperature-dependent Isc properties of the junction, contrary to conventional photodetectors, show an initial rise and then a sharp transition from maximum (3.5 μA) to almost zero near 337 K, corresponding to a metal–insulator phase transition, paving the way for photodetectors with temperature-tunable photoresponsivity. [ABSTRACT FROM AUTHOR]