Effects of Ta, Nb, Ba, and Sb concentration on structural, electrical, and optical properties of SnO2 thin films prepared by metal organic decomposition using spin coating

Abstract

Ta-, Nb-, Ba-, and Sb-doped SnO2 thin films were prepared by the metal organic decomposition (MOD) method using spin coating. The effects of dopant concentration on the structural, electrical, and optical properties were investigated. The growth of polycrystalline films with the tetragonal rutile structure was confirmed by X-ray diffraction and atomic force microscopy measurements. The resistivity of Ta-, Nb- and Sb-doped SnO2 samples decreased to ∼10−3 Ωcm for dopant concentrations of around 1.5–3.0 at.%. The lowest resistivities were obtained for Ta- and Sb-doped SnO2 samples. On the other hand, no decrease in resistivity was observed for Ba-doped SnO2 samples. The band gap energy of Ta-, Nb-, Ba-, and Sb-doped SnO2 samples appeared to be larger than for those prepared by other methods. It was suggested that the structural deterioration may be related to the increase in the band gap energy for MOD prepared samples in addition to the Burstein-Moss effect.