Influence of hydrothermal reaction time on phases, morphologies and optical properties of Sm2O3 thin films

The Sm2O3 thin films were deposited on glass substrates by hydrothermal method using samarium dichloride as a raw material. The influences of the hydrothermal reaction time on the phases, microstructures and optical properties of the thin films were investigated. The as prepared thin films were characterised by X-ray diffraction, atomic force microscopy and UV–Vi absorption. Results show that the grain size, peak intensity and orientation growth of Sm2O3 crystallites thin films increase with reaction time during a 48 h period, and then decrease with further time. The band gap of the as prepared thin films measured by UV–Vi absorption reveals that the variation of the band gap of the thin film with reaction time shows an opposite trend compared with that of the grain size, and the band gap of the thin films is calculated to be 3˙79–3˙95 eV.