The effect of vacuum annealing on graphene

Abstract

The effect of vacuum annealing on the properties of graphene is investigated by using Raman spectroscopy and electrical measurement. Heavy hole doping on graphene with concentration as high as 1.5 × 1013 cm-2 is observed after vacuum annealing and exposed to an air ambient. This doping is due to the H2O and O2 adsorption on graphene, and graphene is believed to be more active to molecular adsorption after annealing. Such observation calls for special attention in the process of fabricating graphene-based electronic devices and gas sensors. On the other hand, because the quality of graphene remains high after thedopingprocess, this wouldbean efficient andcontrollablemethodtointroduceheavydopingin graphene, which would greatly help on its application in future electronic devices. © 2009 John Wiley & Sons, Ltd.