Crystalline TeO2 thin film with chemical bath deposition

Abstract

Tellurium oxide (TeO₂) crystalline thin film has been produced with chemical bath deposition on substrates (commercial glass). Some properties of the films have been investigated by UV/VIS. The spectrum has been studied in terms of as transmittance, refractive index and reflectivity. The monoclinic and orthorhombic forms have been observed for the structural properties in XRD. The structural and optical properties of tellurium oxide thin films have been analyzed at different pHs of the chemical bath. EDX analysis has been used to determine the elemental ratio of tellurium in the films. Some properties of the films change with deposition pH. The concentration of sodium hydroxide was scanned at 2.5×10^-3 M, 5×10^-3 M, 7.5×10^-3 M and 10×10^-3 M at pHs of 10, 11, 11.50 and 12, respectively. The optical properties of the films change with the deposition pH of the chemical bath. Also, the film thickness changes with deposition pH at 12, 11.50, 11 and 10 and the respective thickness values are 900, 586, 657 and 866 nm. The optimum parameters have been determined with 10 mL 2.5×10^-3 M tellurium tetrachloride, 10 mL 2.5×10^-3 M of potassium hydroxide and 2 mL hydrogen peroxide at pH: 10 for producing γ-TeO₂.