Consideration of growth process of diamond thin films in ambient oxygen by pulsed laser ablation of graphite

Diamond thin films were grown on diamond (1 0 0) substrates in oxygen atmospheres by pulsed laser deposition (PLD) using a graphite target. In the optimum oxygen pressure of 5×10–2 Torr, the sp2 bonding fractions can be etched away preferentially and the sp3 bonding fractions remain predominantly on the substrate. At substrate temperatures lower than 400 °C, amorphous carbon generates. At higher than 400 °C, diamond crystallites begin to generate in the amorphous carbon. At the suitable substrate temperatures between 550 and 650 °C, single-phase diamond films consisting of diamond crystal with diameters of 1–5 μm could be grown. Based on the results, the growth process of diamond thin film by PLD is considered.