Doping of Graphene Films: Open the way to Applications in Electronics and Optoelectronics

Graphene films have been regarded as potential materials for future applications in electronics and optoelectronics. Among various synthetic approaches, chemical vapor deposition (CVD) approach can produce large-area graphene films with excellent scalability, controllability, and quality. Graphene doping, that is capable of improving carrier concentration and shifting the Fermi level position of graphene, has become an important pathway for realizing its desired applications. Physical adsorption of dopants on graphene surface can dope the graphene system through surface charge transfer and preserve the graphene lattice; however, the low doping stability strongly hinders its applications. The substitutional doping can achieve fine doping stability by incorporating heteroatoms, such as nitrogen and boron, into graphene lattice, but suffers from low carrier mobility owing to the presence of defects and disorders. In this review, the aim is to provide a comprehensive understanding of application-related doping performance including doping stability, doping uniformity, carrier concentration, carrier mobility, electrical conductivity, and optical transparency. The aim of the review is also to provide an outlook for future doping techniques of CVD graphene films toward various applications.