Tunable Photoresponse by Gate Modulation in Bilayer Graphene Nanoribbon Devices

摘要： Control of absorption and photocurrent conversion is of practical importance for the design of photoelectric devices. In this paper, using simulations, we demonstrate that the photoresponse of a bilayer graphene nanoribbon (GNR) device can be controlled by gate voltage modulation. A vertical gate ?eld shifts the potential on the top and bottom layers in opposite directions, resulting in a continuous change of band gap with applied gate voltage. This ?eld simultaneously facilitates separation of photoexcited electron?hole pairs and gives rise to a photocurrent in a selected photon energy range. The photoresponse of a bilayer GNR device can thus be tuned by adjusting the applied gate voltage. In addition, the light frequency range can be changed by using nanoribbons of di?erent widths. These ?ndings provide a basis for the design of adjustable optoelectronic devices using two-dimensional materials.