Superlow friction and oxidation analysis of hydrogenated amorphous silicon films under high temperature

In the present paper, hydrogenated amorphous silicon films were prepared by plasma enhanced chemical vapor deposition method on the steel and single crystal silicon substrates. The microstructure, thermal stability and high temperature tribological properties of hydrogenated amorphous silicon films were investigated by Raman, FTIR and high temperature tribometer, respectively. The tribotest results were obtained through a comparison of the tribological properties of hydrogenated amorphous silicon films in the temperature ranges of 200 °C to 700 °C. It is found that hydrogenated amorphous silicon films exhibit super low friction of 0.06 at the temperature of 600 °C and 0.05 at the temperature of 700 °C. Raman measurements show that high temperature super low friction of the hydrogenated amorphous silicon film-related friction pair is involved in the oxidation of amorphous silicon films and the steel substrate in ambient air under high temperature during sliding. The oxidation process of hydrogenated amorphous silicon films is also simulated by molecular dynamics method to understand the oxidation mechanism of high temperature superlow friction showing the role of oxidation and it provides the physical insights into the friction process of hydrogenated amorphous silicon films observed experimentally.