Spectroscopical analysis of luminescent silicon rich oxide films

TLDR: In this article, compositional, structural and optical properties of silicon rich oxide (SRO) films containing different silicon excess were investigated using X ray photoelectron spectroscopy (XPS), Raman Spectroscopy, energy filtered transmission electron microscopy (EFTEM) and photoluminescence (PL).

Abstract: Compositional, structural and optical properties of silicon rich oxide (SRO) films containing different silicon excess were investigated using X ray photoelectron spectroscopy (XPS), Raman spectroscopy, energy filtered transmission electron microscopy (EFTEM) and photoluminescence (PL). The XPS-Si2p peaks fitting showed the presence of Si - Si 4 tetrahedra only for the SRO film with the highest silicon excess. Raman spectroscopy revealed amorphous phase silicon in the SRO films with lowest silicon excess; when it was increased, a sharp peak at around 517 cm -1 appeared, which corresponds to crystalline silicon. Si-nanoclusters were slightly observed by EFTEM in the SRO film with the lowest silicon content. They became more evident when the silicon excess was increased, in agreement to Raman spectra. A strong PL was observed in the SRO films with low silicon excess. However, in SRO films with the highest silicon excess, where the silicon agglomeration is greater, the PL practically disappeared. According to these results, we have analysed the dependence of photoluminescence on the composition and structure of the SRO films.