Characteristics of pn junction diode made of multi-layer graphene

The study used multi-layer graphene, synthesized by thermal chemical vapor deposition, as the material for a homo-junction pn device formation. Due to the oxygen adsorption in air, the synthesized pristine graphene behaved as a p-type semiconductor. In order to modulate the graphene semiconductor type, the nitrogen plasma treatment with radio-frequency power as a parameter was used to transfer the semiconductor characteristics. The graphene-based field-effect transistor transfer characteristics were subsequently measured to confirm whether the modified graphene was p-type or n-type. Different nitrogen doping levels affected the diode properties differently. It demonstrated that the rectification effect of the formed pn device was clearly observed using this simple strategy. We also successfully produced this graphene lateral pn device applying a half-wave rectification circuit. The effective formed pn device can be further applied in bipolar junction transistor development. (C) 2019 The Japan Society of Applied Physics