Precise Spatial Photodoping of Lateral Graphene p-n Interfaces

Reliable and accurate spatial doping of 2-dimensional (2D) materials is important for the potential applications of this novel class of materials. Here, we present our work on spatial photo-doping of an h-BN/Graphene/h-BN heterostructure. By optically activating and deactivating the natural defect states in bulk h-BN, which act as remote doping centers for graphene, we change both the carrier density and carrier type in graphene accurately and reversibly by several orders of magnitude. By controlling the position of a spatially resolved light source to only activate photo-dopants in selected areas of the sample, lateral doping modulation was achieved and a PNP junction (PNPJ) device was created. In-situ quantum Hall measurements were used to demonstrate the effectiveness of this doping technique and characterize the electrostatic profile of the PNPJ. This doping technique opens many possibilities to engineer novel device concepts and expand the applications of 2D heterostructures.