On the fabrication of graphene $p$–$n$ junctions and their application for detecting terahertz radiation

A new method for the formation of lateral $p$–$n$ junctions in epitaxial graphene with the use of UV (ultraviolet) radiation is considered. The UV illumination method makes it possible to obtain large-size $p$–$n$ junctions. Such $p$–$n$ junctions are investigated in the photocurrent and photoconductivity modes under irradiation with terahertz radiation. The mechanisms of terahertz photoresponse in graphene $p$–$n$ junctions are discussed.