Optical Properties of Al-Doped TiO2 Thin Films

Un-doped titanium dioxide (TiO₂) and aluminium (Al) doped thin films were prepared by the sol-gel method. TiO₂ sol is mixed with different weight % of aluminium and films were prepared by spin coating. The films were characterised with optical transmittance/reflectance measurements using spectrophotometer. The optical constants (n, k) were determined by envelope method. Optical band gap energy was estimated using Tauc's method and found to be 3.36 and 3.28 eV respectively at 50oC and 150°C respectively.