Nanolithography of the Nanocorral Structure of Chemisorbed Oxygen Atoms on the Graphitic Lattice

Controlled atomic patterning is an attractive tool to fine tune properties of graphitic lattice. Several O-functionalized derivatives of graphitic lattice have been widely studied, e.g., graphene oxide, reduced graphene oxide, and functionalized carbon nanotubes. A controlled patterning of chemisorbed O atom is highly desired to fine tune physical and chemical properties, e.g., bandgap, conductivity, hydrophilicity, reactivity, etc. However, patterning of chemisorbed O on the graphitic lattice at the nanometer scale has not been reported. In this study, using scanning tunneling microscopy (STM), we manipulate chemisorbed O (epoxy) on the graphitic lattice, on demand, on the desired atom, on an atom-by-atom basis. We show that chemisorbed O can be desorbed when an energy exceeding the energy barrier for desorption (-1.3 eV) is supplied as the bias voltage for imaging. This resulted in pristine, defect-free, and clean graphitic lattice at the site of desorption. Nanometer-scale patterns with resolution of oxygen-free regions surrounded by oxygen-rich regions could be achieved by scanning a predefined area. A distinct imaging effects was observed with low and high bias voltage-based scanning which is attributed to the local density of states of the O-functionalized graphitic lattice. Overall, the novel atomic-oxygen nanolithography of graphitic surface opens pathways for studying physicochemical properties of the functional groups in nanometer-scale confinement.