Effects of Molecular Dual Doping and Doping Location in Graphene Field-Effect Transistors

Abstract

Reliable p-type or n-type doping on graphene field-effect transistors was carried out using molecular dopants. Molecular dopants exhibited the enhancement of performance of graphene field-effect transistors compared to pristine graphene field-effect transistors. In addition, dual doping where the molecular dopants are located both on and under the graphene active layer was investigated. The doping location played an important role in charge transport behaviors of graphene field-effect transistors and the order of doping process on graphene also critically affected the device performance. Moreover, we observed that the molecular n-type dopant can lose its n-type doping power and even serve as p-type dopant under specific conditions. Our results provide insights into the strategies to selectively tune and enhance the performance of graphene field-effect transistors utilizing the molecular doping concept.