Abstract
Abstract This study aims to determine the optical properties of thin films which include absorbance, transmittance, energy band gap, and activation energy characterized by UV-Visible spectrophotometer (UV-vis) with a wavelength of 200-1100 nm. Tin dioxide (SnO 2 ) films are prepared by doping various Fluoride ion (F - ) concentrations (0, 5, 10, 15, 20 and 25%) on glass substrates using the sol-gel spin coating method. The absorption edge of SnO 2 thin films was found to accrue from 2.90 to 4.41 at 300 nm wavelength when the F - doped concentration increased from 0 to 25%. Furthermore, the transmittance also increased from 65.5 to 97.8% towards the wavelengths from 300 to 350 nm. However, the band gap and activation energies obtained decreased with a percentage increase in fluorine doping. The energy band gap decreased from 3.55-3.41 eV and 3.90-3.84 eV for direct as well as indirect allowed respectively, while the activation energy decreased from 4.04-1.99 eV. The band-gap energy of SnO 2 thin films also decreased, and the electrons adjustment from the valence to conduction band caused the conductivity of the film to increase.