Laser "Nano"ablation of Ultrananocrystalline Diamond Films

Abstract

The aim of this work was to investigate the excimer laser action (λ = 248, T = 20 ns) on the ultrananocrystalline diamond films grown by CVD technique with different nitrogen gas phase content (0% and 30%). The origin of the films ablation was found to be strongly dependent on laser fluence. A high radiation intensity induces the surface graphitization of the film and a consequent ablation with the rate over 10 nm/pulse. Contrariwise at the fluence below the certain threshold the ablation rate was found to be extremely low (∼10 -2 nm/pulse) and not constant across the thickness in case of the nitrogen doped ultrananocrystalline diamond film. Though the low-rate etching is not accompanied by graphitization a certain structure modification has been detected by a Raman spectroscopy.