Relating hysteresis and electrochemistry in graphene field effect transistors

Hysteresis and commonly observed p-doping of graphene based field effect transistors (FETs) have been discussed in reports over the last few years. However, the interpretation of experimental works differs; and the mechanism behind the appearance of the hysteresis and the role of charge transfer between graphene and its environment is not clarified yet. We analyze the relation between electrochemical and electronic properties of graphene FETs in a moist environment extracted from the standard back gate dependence of the graphene resistance. We argue that graphene based FETs on a regular SiO2 substrate exhibit behavior that corresponds to electrochemically induced hysteresis in ambient conditions, and can be caused by a charge trapping mechanism associated with sensitivity of graphene to the local pH. (C) 2011 American Institute of Physics. [doi:10.1063/1.3665196]