CO₂ laser-assisted local deposition of diamond films by combustion-flame method

Quality of diamond films is strongly dependent on substrate temperatures, which are usually controlled in a range of 600 - 1100°C in most experiments. Although many applications have been achieved with these techniques, diamond film growth is still not possible for substrates that cannot endure such high temperatures for long time. In this study, a continue-wave (CW) CO₂ laser was used to irradiate the growth area on tungsten carbide (WC) substrates during C₂H₂/O₂ combustion-flame deposition in order to maintain required temperature in the growth area while keep the rest of the substrates at a low temperature. The laser power was adjusted between 200 - 600 W to study the effects of laser irradiation on diamond deposition. Surface morphologies of die deposited films were examined by a scanning electron microscope (SEM). Film structures were characterized by Raman spectroscopy. It was concluded that the CO₂ laser irradiation during combustion-flame deposition could raise the temperature at the growth area efficiently. Both laser power and power density have effects on the diamond deposition. Laser irradiation with proper parameters could improve the crystal quality of the diamond films. Based on the experimental results, the CO₂ laser-assisted combustion-flame deposition is a promising method for local substrate heating during diamond film growth.