Effect of Lithium on Physical and Sensing Properties of Titanium Oxide Nanostructured Thin Films Prepared by Chemical Spray Pyrolysis

Abstract

Li-doped titanium oxide thin films are grown through Spray Pyrolysis (SP) method. XRD peaks showed that samples were polycrystalline. The appropriate peak was at (121) equivalent to 2θ = 30.70◦, the Grain size (D) increased from 9.58 nm to 10.17 nm, whereas strain (ε) decreased from 36.17 to 34.08, whilst dislocation density (δ) decreased from 108.96 to 96.68. According to the AFM photo, surface roughness declined (8.08 - 3.67) nm when TiO2 was increased to 4% Li. The average particle size values were 88.78, 85.62, and 60.89 nm for TiO2, TiO2:2 % Li, and TiO2:4% Li, respectively. The transmittance of TiO2 and TiO2: Li films reduced from 85 TiO2 % to 75 % as Lithium content rise from 1 to 4 at%. Research indicates that the absorption coefficient reduces as the lithium content rises, whereas the bandgap energy, extinction coefficient, and refractive index decline as the lithium content rises. The TiO2 gas sensor showed increased resistance at 200 ppm NH3, with 4% Li doping having the highest. Higher Li doping in TiO2 decreases sensor sensitivity to NH3 gas, with a reduction at all concentrations.