Electrical annealing and temperature dependent transversal conduction in multilayer reduced graphene oxide films for solid-state molecular devices

The transversal conductance through thin multi-layered films of reduced graphene oxide was studied as a function of temperature in a solid-state device setup designed for molecular electronic measurements. Upon cooling to cryogenic temperatures, the resistivity of the films increased by about three orders of magnitude compared to the value at room temperature, and this temperature dependence was described by a variable range hopping model. Above a certain threshold voltage the films could be annealed electrically at low temperatures. This electrical annealing resulted in a dramatic decrease in resistivity by up to four orders of magnitude. Upon reheating, the conductivity of the annealed films displayed an almost negligible temperature dependence. These results are promising for the application of reduced graphene oxide as a soft top-contact layer for molecular monolayer devices in the solid-state.