Optical Studies on the Effect of Different Layers of TiO2 Seeded-Template to the Growth of Nanostructured ZnO

Abstract

In this study, Zinc oxide (ZnO) nanostructures have been fabricated on glass substrates coated with Titanium dioxide (TiO2) of different layers, which act as seeded-template, by a solution-immersion method. The substrates were coated with TiO2 by using sol-gel spin coating at five different layers of TiO2: 1, 3, 5, 7 and 9. The effects of the layers to the growth of ZnO nanostructures were observed by using Ultraviolet-Visible (UV-Vis) spectroscopy, Raman spectroscopy and Photoluminescence (PL) spectroscopy. UV-vis spectra of films display the increasing of absorbance properties at visible region as the TiO2 layers increase, as well as at UV region. Meanwhile, at visible region the transparency of TiO2: ZnO films reduce as the layers of TiO2 increase from 1 layer to 9 layers. Raman analysis shows the presence of ZnO in all the TiO2 seeded-templates. From the result, it is confirmed the existence of mixed crystalline structure of both materials in these TiO2: ZnO thin films and PL spectra of the films show seeded TiO2 thin films has lower intensity of visible emission and high ratio of IUV/IVIS compared to the non-seeded TiO2 This contributes to the lower structural defects, oxygen vacancies, impurities and has the most improved optical properties.