The evolution of PL properties of hydrogenated Si-rich silicon carbide/amorphous carbon nano-multilayer films grown by PECVD

Hydrogenated Si-rich silicon carbide (SixC1-x:H)/amorphous carbon (a-C:H) nano-multilayer films have been prepared by PECVD method with different silane mixture gas flow rates at 200 °C. The influence of the silane mixture gas flow rate on the chemical bonds, composition, microstructure, optical band gap and photoluminescence properties of the nano-multilayer films were studied by employing Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy (HRTEM), ultraviolet-visible (UV-vis) and photoluminescence spectroscopy, respectively. The FTIR and UV-vis spectra demonstrated that the incorporation of more carbon atoms into the SixC1-x:H networks is the main reason for the increase of optical band gap of the nano-multilayer films with increase of silane mixture gas flow rate. The Raman and HRTEM showed that there is no any nano-particles in the nano-multilayer films. The photoluminescence mechanisms of the nano-multilayer films was shown to be mainly contributed by band-to-band recombination of the Si-rich SixC1-x:H layers.