Radiation induced changes in amorphous hydrogenated DLC films

Amorphous hydrogenated diamond-like carbon (DLC) films synthesized at room temperature from acetylene gas on quartz glass wafers by means of the direct ion beam deposition method and irradiated with X-ray photons of different energy were investigated. Ionizing radiation induced changes of bonding structure in a-C:H films of different thickness and different density were studied using Raman and infrared spectroscopy and atomic force microscopy. Optical transmittance spectra of the DLC films in UV–vis range were measured as well. The influence of technological deposition characteristics on the optical properties of irradiated amorphous DLC films and the role of the hydrogen in the DLC films were estimated and discussed with the purpose to assess possible application of amorphous hydrogenated DLC films as the protective coatings in radiation detectors. All investigated DLC films showed some increasing tendency of the optical transmittance in the visible and infrared range after the irradiation. Low density PLCH films irradiated with high energy X-ray photons were highly transparent in the whole UV–vis range and indicated possible changes in the bonding structure of the irradiated samples, which have been discussed on the basis of the results obtained during this investigation.