Effect of electron-beam irradiation on graphene field effect devices

Electron beam exposure is a commonly used tool for fabricating and imaging graphene-based devices. Here we present a study of the effects of electron-beam irradiation on the electronic transport properties of graphene and the operation of graphene field-effect transistors (GFET). Exposure to a 30 keV electron-beam caused negative shifts in the charge-neutral point (CNP) of the GFET, interpreted as due to n-doping in the graphene from the interaction of the energetic electron beam with the substrate. The shift of the CNP is substantially reduced for suspended graphene devices. The electron beam is seen to also decrease the carrier mobilities and minimum conductivity, indicating defects created in the graphene. The findings are valuable for understanding the effects of radiation damage on graphene and for the development of radiation-hard graphene-based electronics.