Self-powered In2Se3/PtSe2 photodetector with broadband and fast response

The emerging van der Waals semiconductor In2Se3 has recently gained great attention in the field of optoelectronics, due to its high optical absorption and direct bandgap. Different types of In2Se3 photodetectors have been demonstrated with high responsivity, though the detection speed and wavelength range are limited by the device geometry and its absorption edge. In this paper, we have fabricated an α-In2Se3/PtSe2 heterojunction photodetector. Taking advantage of the high mobility and narrow bandgap of PtSe2, a wide wavelength response from 405 to 1550 nm and fast repose speed of ∼ 127 µs has been achieved in the heterojunction photodetector. Also, benefiting from the strong built-in electric field between In2Se3 and PtSe2, the photodetector can work without any external bias with a responsivity highly at 80 mA/W. This fast self-powered In2Se3/PtSe2 photodetector presents an avenue for future low-energy-consumption optoelectronics.