Microcapacitors at graphene oxide and synthetic polymers prepared by mi‐ crobeam lithography

Carbon-ion microbeam writing was employed for the mask-less production of microscale capacitors in insulating graphene oxide (GO), polyimide (PI) and poly(methyl-methacrylate) (PMMA) foils. The substrates were irradiated by a 5 MeV C beams with micrometer-scale resolution to create conductive strips. The morphology and quality of the created microstructures and compositional changes in the host matrix under the ion microbeam irradiation were studied using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The changes in the structure and elemental composition of the irradiated areas were characterised by Raman micro-spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectroscopy and elastic recoil detection analysis. The microcapacitors with the highest capacitance (in the order of pF) were those prepared on the GO surface. On the other hand, in PI and PMMA, the same carbon-ion irradiation does not induce such a significant enhancement of electric properties and the capacity of the resulting capacitor-like structures is substantially lower.