Microstructural investigation of laser-processed surface of diamonds

Abstract

Laser-cut surfaces of single and polycrystalline diamonds were examined by scanning and transmission electron microscopies. The laser-processed grooves are filled with debris materials composed of textually different types of layered carbons: (i) highly oriented, highly crystalline graphite layer, (ii) oriented microcrystalline graphite layer, and (iii) non-oriented nanocrystalline graphite layer, from the basal (unaltered) diamond surface to the center of the grooves. The observation suggests that the pulsed-laser ablation of diamonds occurs via two-step process: (1) graphitization of laser-irradiated diamond surface, followed by (2) sublimation and oxidation of carbon materials.