Co-doping effect of SnO₂ and ZnO in In₂O₃ ceramics: Change in solubility limit and electrical properties

In this study, SnO₂ and ZnO were co-doped in In ₂O₃, and the phase development and electrical characteristics were examined. When Zn²⁺ was added to 20 at.% Sn ⁴⁺ contained In₂O₃, in which a large amount of In₄Sn₃O₁₂ second phase exists, the amount of the second phase decreased as the content of Zn²⁺ increased, which promoted grain growth and increased carrier mobility. In the case of a simultaneous substitution of Sn⁴⁺ and Zn²⁺ into In ₂O₃ with almost the same atomic ratio, a large grain size without second phase was observed, while small grain sizes with many second phases were developed when Sn⁴⁺ and Zn²⁺ were added with different atomic ratios. The electrical characteristics analyzed by Hall effect measurement showed that the electron mobility and conductivity showed a close relationship with the microstructure, while the carrier concentration was almost constant regardless of the Zn²⁺ content.