Material properties and field-effect transistor characteristics of hybrid organic/graphene active layers

We report on the material properties and device characteristics of field-effect transistors (FETs) consisting of hybrid mono-layer graphene/organic semiconductor active layers. By capping with selected organic and polymeric layers, transformation of the electronic characteristics of mono-layer graphene FETs was observed. The off-state current is reduced while the on-state current and field-effect mobility are either unaffected or increased after depositing π−conjugated organic semiconductors. Significantly, capping mono-layer graphene FETs with fluoropolymer improved the on-off current ratio from 5 to 10 as well as increased the field-effect mobility by factor of two compared to plain graphene FETs. Removal of π−conjugated organic semiconductors or fluoropolymer from graphene FETs results in a return to the original electronic properties of mono-layer graphene FETs. This suggests that weak reversible electronic interactions between graphene and π−conjugated organic semiconductors/fluoropolymer favorably tune the material and electrical characteristics of mono-layer graphene.