The Nouchi group has discovered two methods for inducing oxidation in graphene. In the first, they noted that graphene oxidized while performing Raman spectroscopy. The presence of water is required. They further established that, while exposure to water alone did not change the characteristics of the graphene film, exposure to water simultaneously with UV irradiation did change the electron transport properties of the film.
In the second experiments, the group explored the reaction between graphene and oxygen caused by UV irradiation, and the physisorption of oxygen molecules when a gate voltage is applied to graphene field effect transistors. Irradiation of positively biased graphene gates results in oxygen desorption, while similar irradiation of negatively biased gates results in etching of the graphene. This etching proceeds predominately from the edges.
N Mitoma, R Nouchi, and K Tanagaki, “Photo-oxidation of graphene in the presence of water”, arXiv:1311.3447.
N Mitoma and R Nouchi, “Gate-controlled ultraviolet photo-etching of graphene edges”, arXiv:1311.3452.