Pulsed laser deposition of hydrogenated amorphous carbon films from a polymeric target

The phenylcarbyne polymer possesses a diamond-like structure. Because of its special structure, this polymer can be converted into diamond-like carbon phases at atmospheric pressure by thermal decomposition. In this article, we report on the growth of hydrogenated amorphous carbon films (a-C:H) films by pulsed laser (KrF excimer, λ = 248 nm) ablation of a phenylcarbyne polymer target under vacuum. a-C:H films were deposited with various laser fluences and at different substrate temperatures. Chemical and structural characteristics of these films were analyzed using X-ray-excited Auger electron spectroscopy (XAES), photoelectron loss spectroscopy (PELS), and Raman spectroscopy. It was found that the fourfold-coordinated component increases with laser fluence at 80 °C or increases with temperature increasing from 25 °C to 60 °C at a fluence of 1×10⁹ W/cm². When the deposition temperature is increased from 60 °C to 200 °C at a fluence of 1×10⁹ W/cm², the graphitic component increases. The variation in chemical structures of these films is explained in terms of the changes in the fraction of sp²-bonded clusters and changes in the termination of the graphitic clusters and sp³-bonded networks by hydrogen in the a-C:H films.