Synthesis and structural evolution of hydrogenated amorphous silicon carbide thin film with carbon nanostructures

Abstract A new hydrogenated amorphous silicon carbide (a-SiCx:H) thin film with carbon nanostructure is grown through plasma enhanced chemical vapor deposition (PECVD) method. The structural evolution and growth mechanism of the as deposited a-SiCx:H thin film are explored and further discussed with different substrate temperatures. The results show that the structure of the a-SiCx:H thin film is a multiphase structure of carbon nanostructures embedded into C Si O( H) amorphous matrix, and the carbon nanostructure is a spheroidal graphite-like structure. With increasing substrate temperature, the carbon nanostructure gradually grows up through incorporation with surrounding nanostructures. When the substrate temperature increases further to 300 °C, the ultrafine basic structure units of graphite are found within the carbon nanostructure. In addition, the disorder of the thin film first increases and then decreases with increasing substrate temperature, which give rise to band tail states among the π-π⁎ band gap. The change of structure of as synthesized a-SiCx:H thin film with different substrate temperatures supports the sub-plantation model. Furthermore, a tunable optical band gap depended on structure of the carbon nanostructures is demonstrated at different substrate temperatures, which may bring about a potential of application.