Thin film preparation of silicon nanocrystals embedded in silicon oxide by sol-gel method

Abstract

In this paper, nano silicon powders were prepared by the grinding technique and subsequently mixed in sol-gel of Tetraethylorthosilicate and ethanol solution. The silicon dioxide films synthesized from the sol-gel solution were preliminary studied in the term of the optical property as a refractive index (n) by varying the aging time and annealing temperatures. By using a Fourier transform infrared spectroscopy technique, the obtained x-composition values of the SiOx films were extended from 1.67 to 1.98 with a decreasing time of the aged sol-gels. In addition, the lower x-composition value can be controlled by increasing the annealing temperatures from 60◦C to 500◦C. The prepared films from the precursor of nano-silicon powder suspension were characterized by photoemission spectroscopy and Raman spectroscopy in order to obtain more understanding of the chemical composition and silicon nano-crystallite quality, respectively. Presenting the spectra broadening and the frequency downshifting from 521 cm−1 was caused by the quantum size effect.