Vibrational study of hydrogen bonding to ion irradiated diamond surfaces

Abstract

High resolution electron energy loss spectroscopy has been used to probe hydrogenated diamond film surfaces exposed to 1keV Ar+ ions at a dose of ∼1015cm−2 and thermal annealing. The defects induced on the upper atomic layers were identified with regard to the different hydrogenated species hybridization states as well as their thermal stability. Ion irradiation resulted in the coexistence of a partially hydrogenated disordered near surface region including CH species bonded in sp, sp2, and sp3 bonding configurations and CC dimers. Thermal annealing of the ion beam irradiated hydrogenated surface leads to complete hydrogen desorption at ∼650°C. This temperature is significantly lower compared to a well defined diamond surface for which an annealing temperature above 900°C is needed.