Si-doping for the protection of hydrogenated diamond-like carbon films in a simulated atomic oxygen environment in low earth orbit

Yokota, Kumiko*; Tagawa, Masahito*; Kitamura, Akira*; Matsumoto, Koji*; Yoshigoe, Akitaka ; Teraoka, Yuden; Fontaine, J.*; Belin, M.*

The effect of hyperthermal atomic oxygen (AO) exposure on a surface property of Si-doped DLC was investigated. Two types of DLC were tested which contain Si atoms approximately 10 at% and 20 at%. Surface analytical results of high-resolution X-ray photoelectron spectroscopy using synchrotron radiation (synchrotron radiation photoemission spectroscopy; SR-PES) as well as Rutherford backscattering spectroscopy (RBS) have been used for characterization of the AO-exposed Si-doped DLC. It was identified by SR-PES that the SiO layer was formed by the hyperthermal AO exposure at the Si-doped DLC surface. RBS data indicates that AO exposure leads to severe thickness loss on the non-dope DLC, in contrast, SiO layer formed by the hyperthermal atomic oxygen reaction at the Si-doped DLC protects the DLC underneath the SiO layer.