Charge transport and optoelectronic process in an atomically thin p-n junction

Heterostructures based on atomically thin van der Waals materials provide an unprecedented opportunity in new materials design. In particular, the ability to assemble two-dimensional (2D) materials into artificial heterostructures with atomically sharp interfaces, combined with recent rediscoveries of transition metal dichalcogenides as an atomically thin semiconductor, enables to build the unique 2D semiconductor heterojunction for fundamental studies as well as device applications. In this talk, we present the electronic and optoelectronic processes in an atomically thin p-n junction consisting of vertically stacked WSe$_{2}$ and MoS$_{2}$ monolayers. Unlike conventional p-n junctions, tunneling-mediated recombination governs the overall charge transport, and gate-tunable photovoltaic response is driven by charge transfer at the atomically sharp interface with large band offsets. Furthermore, the fully vdW heterostructured vertical p-n junctions with graphene electrodes will be discussed.