Characterization of surface graphitic electrodes made by excimer laser on CVD diamond

When a diamond graphitization process is induced, for example by excimer laser which irradiates the diamond surface, two phenomena occur: diamond graphititization and graphite ablation. The figure shows the physical evolution of the average height of the graphitic spots obtained after laser-diamond interaction, at laser fluence of 5 J/cm2, with respect to the number of pulses. The measurements were obtained by AFM investigations (zero level refers flat unirradiated diamond surface). For one and two pulses it dominates a swelling phenomenon which represents the diamond graphitization process (the swelling is due to different mass density between diamond and graphite phases), while for four and eight pulses the graphite ablation dominates generating crates with increasing depth.