Probing the states around the charge neutrality point of reduced graphene oxide with time-resolved gated Kelvin Probe Force Microscopy

In this work, we performed gated Kelvin Probe Force Microscopy on reduced graphene oxide thin-film transistors with time transient. This enabled us to probe the electronic density of states around the charge neutrality point in reduced graphene oxide thin film. The charge neutrality point is of significance to know the nature of the intrinsic doping of the thin film and the switching of the majority carriers in the transistor devices. We measured the transfer characteristics of the reduced graphene oxide transistor devices to estimate the intrinsic charge neutrality point. The results were in good agreement with the time-resolved gated surface potential measurements obtained using Kelvin probe force microscopy. We propose that gated time-resolved measurement of these semi-metals can be an effective tool to study the nature of electronic states.