The properties of polymer-like amorphous hydrogenated C thin films having a low defect density were studied. The films were implanted with C ions to doses ranging from 1012 to 1016/cm2. Optical absorption measurements revealed a narrowing of the optical band-gap; thus suggesting that the introduction of a large number of defect states during implantation resulted in a broadening of the band tails only after exceeding a threshold dose of 1015/cm2. Nuclear reaction data also suggested that a reduction in the H content of the film coincided with film-thinning.

Studies of Carbon Ion Self-Implantation into Hydrogenated Amorphous Carbon Films. R.U.A.Khan, D.Grambole, S.R.P.Silva: Diamond and Related Materials, 2000, 9[3-6], 675-9