High blue-near ultraviolet photodiode response of vertically stacked graphene-MoS2-metal heterostructures

We present a study on the photodiode response of vertically stacked graphene/MoS2/metal heterostructures in which MoS2 layers are doped with various plasma species. In comparison with undoped heterostructures, such doped ones exhibit significantly improved quantum efficiencies in both photovoltaic and photoconductive modes. This indicates that plasma-doping-induced built-in potentials play an important role in photocurrent generation. As compared to indium-tin-oxide/MoS2/metal structures, the presented graphene/MoS2/metal heterostructures exhibit greatly enhanced quantum efficiencies in the blue-near ultraviolet region, which is attributed to the low density of recombination centers at graphene/MoS2 heterojunctions. This work advances the knowledge for making photo-response devices based on layered materials. (C) 2014 AIP Publishing LLC.