Air‐Stable Symmetric Ambipolar Field‐Effect Transistors Based on Reduced Graphene Oxide‐OTS Self‐Assembled Monolayer Heterostructure

Abstract Graphene has attracted great interest in the past decade due to its unique band structure and physical properties such as quantum electronic transport, extremely high mobility, high elasticity and optical properties. Graphene is generally obtained by mechanical exfoliation, epitaxial growth, chemical vapor deposition and chemical synthesis approaches, wherein the reduction of graphene oxide (GO) is a practical approach to synthesize large‐scale graphene. Via reduction, highly conductive reduced graphene oxide (RGO) can be obtained, which has electrical and optical properties analogous to those of graphene. However, Field‐effect transistors (FETs) based RGO typically exhibit p‐type in ambient rather than the ambipolar behavior of intrinsic graphene, due to the doping effect induced by substrate and the air. Meanwhile, large hysteresis accompanies with the p‐type transistor. Here, a self‐assembled monolayer (SAM) of octadecyltrichlorosilane (OTS)‐RGO heterostructure is developed, in which RGO is sandwiched between OTS SAMs. The heterostructure passivates the RGO device and eliminates the doping of graphene from the surroundings. The obtained RGO FETs exhibit air‐stable symmetric ambipolar behavior with Dirac point at 0 V gate voltage and negligible hysteresis. This approach will also be applicable to pristine graphene and other two‐dimensional materials to obtain the intrinsic properties under ambient conditions, thereby promoting the research and applications of two‐dimensional materials.