INFLUENCE OF THE SUBSTRATE TEMPERATURE ON TiO2 THIN LAYERS DEPOSITED BY THE DIRECT CURRENT MAGNETRON SPUTTERING TECHNOLOGY

Abstract

In this study, Anatase thin films of titanium dioxide (TiO[Formula: see text] are deposited by the Direct Current (DC) magnetron sputtering technique on glass substrate for future application in gas sensors. In our work, we focused and discussed the effect of various substrate temperatures [Formula: see text]C, [Formula: see text]C and [Formula: see text]C, and film thicknesses 142, 220 and 410[Formula: see text]nm, respectively, in order to study the structural and optical properties of the TiO2 thin films. The crystalline structure and optical properties of TiO2 nanoparticles were investigated using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), Atomic Force Microscopy (AFM), Raman spectroscopy and UV–visible spectroscopy. The formation of the Anatase TiO2 with Tetragonal crystal structure has been confirmed with XRD. UV–visible spectrophotometry characterization of the developed thin films showed that all the films had an optical transmission greater than 92% in the visible region. In addition, the obtained direct and indirect optical band gaps using the Tauc plot are 3.66, 3.34[Formula: see text]eV at [Formula: see text]C 3.74, 3.37[Formula: see text]eV at [Formula: see text]C and 3.71, 3.37[Formula: see text]eV at [Formula: see text]C, respectively. Forouhi–Bloomer (FB) physical model has been used to obtain the refractive index and extinction coefficient by fitting theoretical transmittance curves to experimental ones. The optical refractive index is found to vary from 2.350 for [Formula: see text]C, 2.1499 for [Formula: see text]C and 2.1420 for [Formula: see text]C. Moreover, we have obtained an extinction coefficient [Formula: see text] ([Formula: see text] of around [Formula: see text] for both substrate temperatures [Formula: see text]C and [Formula: see text]C, and around [Formula: see text] for the [Formula: see text]C.