Optical investigation on dielectric multilayers prepared by sol-gel method

Abstract

The challenging optical performance of the thin film has depending on the selected materials, the number of alternative layers (or stacks), thin film deposition methodologies, etc. In this paper reporting, the experimental investigations of the alternate stacking of TiO2/SiO2 multilayers on the silicon substrates by using sol-gel and spin-coating method. The prepared seven (7S) and nine stacks (9S) of dielectric reflectors (TiO2/SiO2) were characterized to examine the reflectance and related functional groups by UV–Visible spectrophotometer and Raman spectroscopy. The higher and broader photonic bandgap (PBG) achieved in the ultraviolet and visible spectral region by enhanced number of stacks (9S) which was showed the highest reflectance. Further, the Raman spectra confirmed the existence of silicon (512 cm−1), anatase-TiO2 (Eg, 144 cm−1) and week bands of SiO2 (410, 487 & 919 cm−1). Finally, the relative reflectance enhancement of 54.3% was noticed by the highest number of stacks which will be useful as a back side reflector in solar cells.