Selective removal of single-layer graphene over double-layer graphene on SiO2 by remote oxygen plasma irradiation

Graphene sheet transferred onto the SiO2 substrate has various types at different regions such as single-layer graphene (SLG), double-layer graphene (DLG), and multi-layer graphene (MLG). These layers were identified by Raman analysis of 2D band position around 2700 cm−1 and full width at half maximum (FWHM). The transferred graphene sheets on SiO2 were remotely irradiated by oxygen plasma without energetic ions at a room temperature. At the beginning of the oxygen plasma irradiation, the carbons on the surface of the graphene sheets were oxidized and the 2D-FWHMs were broadened due to an increase of defects on the basal plane. By controlling the plasma irradiation time up to 120 min, selectively stripping away the SLG regions on the SiO2 surface was observed while leaving the other DLG and MLG regions. The difference in attractive forces resulted in favorable desorption of carbon atoms occurred in the oxidized SLG regions on SiO2 surface by the remote oxygen plasma irradiation.