2D materials and heterostructures for applications in optoelectronics

We present the realization and optoelectronic characterization of p-n junctions based on two-dimensional semiconductors. Such junctions may be realized by lateral or vertical arrangement of atomically thin p-type and n-type materials. In particular, a WSe2 monolayer p-n junction, formed by electrostatic doping using a pair of split gate electrodes, and a MoS2/WSe2 van der Waals type-II heterojunction are presented. Upon optical illumination, conversion of light into electrical energy occurs in both devices. Under forward bias, electrically driven light emission is achieved. Measurements of the electrical characteristics, the photovoltaic properties, and the gate voltage dependence of the photoresponse will be discussed.