Photochemical effect on diamond film surfaces induced by extended exposure to UV light

The photochemical effect induced on the diamond film surfaces by extended exposure to UV light in air and at room temperature, was studied by Fourier-transform infrared (FTIR) spectroscopy. High quality combustion deposited diamond films were prepared for this study, as revealed by the sharpness of the corresponding typical Raman band at 1332 cm−1 and by the weak non-diamond carbon features around 1550 cm−1. Some chemical species were chemisorbed on the diamond film surfaces during the synthesis, and were studied through the FTIR spectral changes produced when the diamond films are subjected to different UV treatments. The UV treatments were applied continuously during 1 and 2 days. The initial amount of hydrogen and oxygen chemisorbed on diamond film surface was modified through the different exposure periods, suggesting that the photochemical effect was basically controlled by the UV radiation dose and that a reconstruction of the diamond film surface take place during the UV treatment. The role of the oxygen radicals, such as O3 (ozone) and O∗ (atomic oxygen), produced by the UV radiation on the diamond film surface is discussed, as well.