Influence of magnesium doping on the structural and optical properties of tin (II) oxide thin films deposited by electron beam evaporation

Single-phase polycrystalline magnesium-doped tin oxide (MgxSn1−xO; x=0, 0.04, and 0.08) thin films were deposited by electron beam evaporation on the glass substrate. X-ray diffraction analysis showed that the peaks intensity of the polycrystalline α-SnO thin films increased along with the increasing Mg content. The crystallite size calculated from X-ray diffraction data decreased by increasing the Mg doping concentration, which was also confirmed by atomic force microscopy. The stoichiometry and thickness of the thin films were determined by Rutherford backscattering spectroscopy. An increase in both the optical transmission (57–95%) and band gap (2.5–2.82 eV) of the MgxSn1−xO thin films were observed which were investigated by UV–vis spectroscopy. Photoluminescence of MgxSn1−xO thin films revealed that there were two extra peaks at 482 nm and 550 nm due to the crystal defects introduced by the Mg doping and these peaks become weaker and shifted to longer wavelength by increasing the Mg doping concentration.