Effects of Structural, Electrical and Raman Properties of Al-Doped TiO2 Thin Films Acquired by Sol-gel Spin Coating Method

Abstract

Titanium dioxide (TiO2) is well known for its excellent photocatalytic properties and potential applications, particularly in gas sensing. However, its high resistivity can limit its performance in such applications. This study explores the effect of aluminium (Al) doping on the structural, electrical, and Raman properties of TiO2 thin films, to optimise their performance for gas sensor applications. TiO2 films were prepared with varying Al concentrations (1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, and 6 wt.%) using the sol-gel spin coating method. The films were characterised using X-ray diffraction (XRD), current-voltage (IV) measurements, and Raman spectroscopy. The results show that doping with 3 wt.% Al significantly improves the structural, electrical, and Raman properties of the films, yielding the lowest resistivity value of 734.873 Ω-cm and the most pronounced anatase peak in the Raman spectra. These findings indicate that 3 wt.% Al doping optimises TiO2 thin films for gas sensor applications, offering potential improvements for environmental and industrial sensing technologies.