Metal–semiconductor–metal UV photodetector based on Ga doped ZnO/graphene interface

We have inserted single layer graphene under Ga doped ZnO to excite surface plasmon in metal-semiconductor-metal (MSM) UV photodetector.The fabricated MSM photodetector exhibited a room temperature (RT) responsivity of 48.37 A/W at wavelength of 350 nm and UV-to-visible rejection ratio of about three orders of magnitude.The induced surface plasmon at the interface of Ga doped ZnO and underlying grapheme may play an important role in improving the performance of the ZnO based UV photodetectors.

Fabrication and characterization of metal–semiconductor–metal (MSM) ultraviolet (UV) photodetector (PD) based on Ga doped ZnO (ZnO:Ga)/graphene is presented in this work. A low dark current of 8.68 nA was demonstrated at a bias of 1 V and a large photo to dark contrast ratio of more than four orders of magnitude was observed. MSM PD exhibited a room temperature responsivity of 48.37 A/W at wavelength of 350 nm and UV-to-visible rejection ratio of about three orders of magnitude. A large photo-to-dark contrast and UV-to-visible rejection ratio suggests the enhancement in the PD performance which is attributed to the existence of a surface plasmon effect at the interface of the ZnO:Ga and underlying graphene layer.