▎ 摘　　要

The synthesis of lateral heterostructures of graphene and hexagonal boron nitride (h-BN) has attracted attention due to the ability to broadly tune the electronic properties of the hybrid monolayer. Conventional synthesis methods for lateral heterostructures rely on chemical vapor deposition on metal surfaces, and application of the heterostructure in devices requires transfer of the material onto a suitable substrate during which the sample is susceptible to damage or contamination. Herein, a transfer-free synthesis method to produce lateral heterostructures of graphene and h-BN by chemical conversion of epitaxial graphene on 6H-SiC(0001) is demonstrated. X-ray photoelectron spectroscopy measurements confirm the substitution of graphene with h-BN, while scanning tunneling microscopy reveals that the h-BN domains reside in-plane with graphene forming an interface along the zig-zag direction. Raman spectroscopy measurements provide insight into the reaction mechanism in which h-BN is substituted for graphene at defect sites thereby reducing the defect density in the lateral heterostructure. The development of scalable, transfer-free synthesis methods for lateral heterostructures of graphene and h-BN, as demonstrated in this work, is expected to facilitate a route toward large-scale synthesis of 2D semiconductors and atomically thin circuitry directly on-chip.