Formation of Graphene P-N Junction Arrays Using Soft-Lithographic Patterning and Cross-Stacking

Two key issues in graphene-based p-n junction applications are the manipulation of the type and density of carrier in graphene and the development of a facile fabrication process. Here we reported the formation of graphene films with tunable carrier type by doping of ethoxylated polyethylenimine (PEIE) and Au nanoparticles (NPs). The carrier density of doped graphene can be tuned by altering the concentration of the dopant solutions. The doping effects of PEIE and Au NPs on graphene were monitored by resonant Raman spectroscopy and electrical transport measurements. Graphene p-n junction arrays were assembled by simple soft-lithographic patterning and cross-stacking of n-and p-type doped graphene films, showing a graphene p-n junction behavior with two VCNDP.