Abstract
VO2 thin film is deposited on glass substrate by using spin-coating technique. Tungsten (W) has been doped as acidic solution to the precursor of vanadium solution. Energy gap has been investigated via absorption coefficient to explore its value with and without W doping. Reflectance spectroscopy results showed that there is a clear difference using few percentages of W doping. Optical transmissions have found for undoped and W-doped VO2 thin film are approximately 75% and 35%, respectively. Empirical models of refractive index and optical dielectric constant are investigated.