A graphene P–N junction induced by single-gate control of dielectric structures

Abstract

Graphene has great application prospects in the field of optoelectronics. We investigate a field effect transistor with a graphene channel. Carrier density and chemical potential of the channel can be spatially modified by topping the channel with dielectric structures consisting of pure and lithium enriched SU-8 layers. As an example, we demonstrate that application of a single-gate voltage can induce a P–N junction to a channel with an appropriate dielectric architecture. Electronic and photoelectric properties of the junction are studied. The photocurrent mapping is investigated, which clearly shows the origin of the photocurrent from the P–N junction. The proposed technology makes fabrication of graphene-based photodetectors simple and flexible, and may also be interesting for the development of future optoelectronic components using other two-dimensional materials.