Fabrication, characterization of TiO$_2$/SiO$_2$ multilayers using sol-gel spin coating method

The TiO$_2$/SiO$_2$ alternating multilayers of one-dimensional photonic crystals (1DPCs) was fabricated by the sol-gel process and a spin coating method. This study investigated the possibility of creating a better solar cell back reflector by introducing maximum and broader reflection towards longer wavelength spectral region with effect of optimal thin films. After the fabrication of 1DPCs, the optical properties were investigated by Raman spectroscopy, Fourier infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-vis) and scanning electron microscopy (SEM). From the results, the Raman spectra exhibited notable peaks and indicates the presence of anatase TiO$_2$ and SiO$_2$ layered structures. Furthermore, the highest reflectance was observed in the visible region and shifting into the longer wavelength spectral region due to the increment of alternative layers (stacks). These structural and morphological results are encouraging for the realization of TiO$_2$ and SiO$_2$ materials for various applications, including LED and photovoltaics.