A study of the topography of a glassy carbon surface following low-power radio-frequency oxygen plasma treatment

The topography of a glassy carbon surface following low-power radio-frequency (rf) oxygen plasma treatment has been studied by scanning tunnelling microscopy (STM). The low-power rf oxygen plasma treatment was found to reveal the inner structure of the glassy carbon at the surface being etched. This phenomenon is attributed to differential etching effects of the plasma at the glassy carbon surface. Long duration low-power rf oxygen plasma etching exposes various topographical features associated with glassy or more crystalline carbon domains. The large proportion of ovoid-shaped nano-sized features found following extended etching have smoothly curved surfaces where well-ordered atomic arrangements are found. The structure of these ovoids is believed to arise from localised graphitic regions having spiral and layer-by-layer packing.