Hydrogen effects on the post-production modification of diamond-like carbon produced by pulsed laser deposition

This work utilizes Raman spectroscopy to examine the thermal annealing of diamond-like carbon (DLC) films produced by pulsed laser deposition (PLD). Post-production modification of DLC films by atomic hydrogen etching reveals distinct results and is observed for the first time. Both ex-situ and in-situ thermal annealing and annealing with atomic hydrogen on the as-prepared DLC samples are compared herein. The Raman spectra reveal that the typical D- and G-bands evolve from unresolved to well separated above 400°C as the temperature increases from room temperature to 700°C. Atomic hydrogen enhances the annealing process at temperatures above 500°C. Thermal annealing transforms the DLC films into graphitic structures while atomic hydrogen etches away the disordered carbons according to both the ex-situ and in-situ Raman spectra.