Sub-10 nm oxidation and etching of graphite using field emission scanning Probe lithography

We employ an atomic force microscope operated under ambient conditions for a resist-free patterning of HOPG and exfoliated graphite nanosheets. The nanostructuring is realized through an electrochemical surface oxidation induced by low-energy electrons field emitted from the tip of an AFM cantilever in close proximity to the sample surface. Unlike previous approaches, we positioned the cantilever tip several tens of nanometers above the surface-adsorbed water layer, rather than within it, making the beam diameter of the field emitted electrons the limiting factor for the achievable patterning resolution. This approach enabled the growth of non-volatile oxide species as well as a direct etching of material with resolutions well below 10 nm under ambient conditions. The tip-written structures were subsequently analysed using Raman spectroscopy and conductive AFM measurement.