Oxygen adsorption effect on nitrogen-doped graphene electrical properties

Abstract

A simple method was found to observe the semiconducting behavior of graphene using the O2 gas adsorption property. Graphene was synthesized by thermal chemical vapor deposition with NH3 as the nitrogen doping source. The current response increased significantly when the p-type graphene was exposed to an O2 environment. The current response decreased gradually when the nitrogen content was increased. When the NH3 flow rate was increased to 80 sccm during graphene synthesis, the p-type graphene becomes n-type and the nitrogen-doped graphene current response clearly decreases during O2 gas adsorption measurements. We measured the graphene Dirac point using a field-effect transistor to define the graphene semiconducting properties. These results show that gas adsorption measurements can reveal the graphene semiconducting performance and also the n-type graphene synthesis conditions.