Graphene p-n junctions have important applications in the fields of optical interconnection and low-power integrated circuits. Most current research is based on the lateral p-n junction prepared by chemical doping and other methods. Here, we report a new type of pure graphene oxide (pGO) vertical p-n junctions which do not dope any other elements but only controls the oxygen content of GO. The I-V curve of the pGO vertical p-n junction demonstrates a remarkable rectification effect. In addition, the pGO vertical p-n junction shows stability of its rectification characteristic over long-term storage for six months when sealed and stored in a PE bag. Moreover, the pGO vertical p-n junctions have obvious photoelectric response and various rectification effects with different thicknesses and an oxygen content of GO, humidity, and temperature. Hall effect test results show that rGO is an n-type semiconductor; theoretical calculations and research show that GO is generally a p-type semiconductor with a bandgap, thereby forming a p-n junction. Our work provides a method for preparing undoped GO vertical p-n junctions with advantages such as simplicity, convenience, and large-scale industrial preparation. Our work demonstrates great potential for application in electronics and highly sensitive sensors.
Keywords: graphene oxide; undoped p–n junction; vertical p–n junction.