Optical characterization of SnO2 nanostructure thin films, annealed at different temperatures

SnO2 nanostructure thin films were deposited on glass substrate at 450 °C by chemical spray pyrolysis (CPS) technique and then annealed at different temperatures; 450, 550 and 650 °C for 1 h. X-ray diffractions (XRD) of samples showed that grain size of thin films grows gradually from 48 nm for (as prepared sample) to 55 nm (for annealed at 650 °C sample). Transmittance spectra indicated that with increasing the annealing temperature up to 550 °C the transmittance is considerably decreased from 90% to ∼83%, and then increases to 89% for the samples annealed at 650 °C. It is also found that the band gap is gradually decreases with increasing the annealing temperature. PL spectra are shown an intense and broad emission at 434 nm for as prepared sample and that annealed at 450 °C and 550 °C, and a weak broad peak for sample that annealed at 650 °C.