Study on the electrical properties and conductive mechanism in Sb_xSn_1-XO₂ solid solution system

This paper reports a study on the solid solution composition and electrical conductivity in Sb_xSn_1-xO₂ gas sensing materials, prepared by chemical coprecipitation method. The experimental results show that the solid solution is formed when 0≤x≤0.30. It is found that the conductance of the samples increases over ten times when doped with trace Sb(x=0.005) , and still increases while x≤ 0.04, but slowly decreases when x changes from 0.04 to 0.30. The reason for the conductance change and conductive mechanism are discussed in terms of the valence-variable defects, Sb^o_Sn and Sb′_Sn, in the system. The relative content of Sb⁵⁺ and Sb³⁺ ions, coresponding to the defect equilibrium , was estimated by XPS analysis. The A. C. impendance spectroscopy technique also demonstrated the above conductivity-composition behavior.