A Bifunctional Tunneling Device for Photodetection and Electroluminescence Using van der Waals Heterostructure

Abstract

Two‐dimensional (2D) materials are widely used in various optical, electronic, and optoelectronic devices. However, the realization of visible light emission and near‐infrared photodetection functions in a single device remains a challenge. Here, an integrated dual‐functional device is developed by manipulating the excitons of WS2 within a graphene/hBN/WS2/graphene heterostructure. When operating as a photodetector at low external bias, the dark current is well suppressed by the hBN layer. With the excellent two‐photon absorption (TPA) property of monolayer WS2, the photoresponse range of the photodetector can be extended to the near‐infrared region, achieving a responsivity of up to 0.19 mA/W at 1145 nm. At high external bias, the device can work in light‐emitting mode, in which the electroluminescence (EL) wavelength can be tuned via gate voltage. This atomically thin device opens up possibilities for applications in miniaturized display, sensing, and monitoring systems.