Optical properties of cerium-doped SiN_x thin films containing silicon nanocrystals

In this work, we investigate the optical properties of silicon nitride doped with Cerium: Ce: SiN_0.38 and Ce: SiN_0.55 films produced by thermal evaporation deposition. Silicon nanocrystals (Si-Ncs) incorporated silicon rich-silicon nitride films (SiN_x<1.33) were developed on Silicon substrate using Plasma Enhanced Chemical vapor technique (PECVD). The GIXRD and Raman analysis show the formation of Si-Ncs in two layers studied, SiN_0.38 and SiN_0.55 with the average size of 6 and 3 nm, respectively. The morphology, structure and chemical properties of annealed Ce doped SiN_x were investigated by energy-dispersive X-ray spectroscopy (EDS), scanning- electron- microscopy (SEM) and elemental mapping, demonstrating that Ce was integrated into the SiN_x layer. Si-Ncs size’s effect on the photoluminescence (PL) response after doping by evaporation is studied. Layers with the small Si-Ncs exhibited a strong increase in the PL intensity in the blue region. Energy transfer between the small Si-Ncs and the Ce is the probable source of enhanced PL emission. The layers with large Si-Ncs did not show any indication of a Ce ion interaction.