Localized deoxygenation and direct patterning of graphene oxide films by focused ion beams

Exposure to controlled doses (~4.65 × 10(-3) to 2.79 × 10(-2) nC/μm(2) ion fluence) of Ga ions via a focused ion beam (FIB) deoxygenates graphene oxide (GO) and increases the electrical conductivity in 100 × 100 μm(2) patches by several orders of magnitude compared to that in unexposed GO. Raman spectra and the carbon/oxygen ratio in exposed areas are indicative of chemically reduced graphene oxide (rGO). This novel FIB-induced conversion technique is harnessed for the direct imprinting of complex micrometer-scale shapes and sub-20-nm lines of rGO in insulating films and flakes of GO establishing the capability of generating features varying in size from approximately tens of nanometers to approximately hundreds of micrometers in a maskless, efficient manner.