Electrical conductivity and X-ray sensing properties of TiO2:Cr thin film synthesised by chemical bath deposition method

Abstract

X-ray sensing properties of chromium (Cr) doped titanium dioxide (TiO2) thin films synthesised by a chemical bath deposition method have been reported. Characterisation reports reveal that the films are polycrystalline and possess anatase phase of TiO2. There is no change of its crystalline phase after the doping of Cr. However, the average crystallite size is found to increase from 9 to 10 nm and the optical band gap decreased from 3.26 eV to 3.14 eV after the doping. The doping also enhanced the electrical conductivity of the films. The electrical conductivity under dark condition is increased from 1.11×10−2 to 1.58×10−1 S/(cm) after the doping of 0.10 M Cr. Similarly, the same under X-ray irradiation is also increased from 2.22×10−1 to 5.25×10−1 S/(cm). The doping influenced the detection quality of the films. The rise time of radiation-induced current is found to decrease from 0.91 to 0.84 s whereas the decay time increases from 1.18 to 1.32 s after the doping of 0.10 M Cr. The detection sensitivity of the films is discussed in regards to change in concentration of charge carriers as well as the structural changes occurred after the doping.