Mg doping effect on the properties of SnO2 thin films synthesized by dip-coating method

Abstract

Undoped and Mg doped SnO2 thin films were deposited on glass substrates using dip-coating method for the first time. X-ray diffraction analysis of the films revealed a tetragonal rutile phase. A decrease in crystallite size is observed as the Mg doping increases. The transmittance spectrum exhibits a decrease in transmittance from 87% to 62% as the Mg content is increased. The optical band gap narrows from 3.97 eV to 3.93 eV with the increasing of Mg content. MEB showed an increase of grain sizes with increase in Mg concentration. The RMS roughness increases with Mg doping content. FTIR showd O–Sn–O, Sn–OH, Mg–O, and OH–Mg–OH vibration modes. PL spectra indicated that the incorporation of more Mg2+ into the lattice of SnO2 creates additional oxygen vacancies, leading to an increase in the PL emission intensity in the films. A transition from n-type to p-type conduction was observed at 9 wt% Mg doping.