Reaction sintering behavior and electrical properties of a Ga-doped ITO system

In this study, we investigated the characteristics of densification, phase formation, and electrical properties during reaction sintering when a Ga-doped ITO, with 10 at% Sn, served as the target material. Results showed that Ga doping enhanced the densification of ITO at a relatively low sintering temperature. Interestingly, the 1 at% Ga- and 20 at% Ga-doped samples showed shrinkage values of 19.5% and 23.0%, respectively, despite the fact they both starting shrinking at the same temperature. In addition, the second phase Ga_3-xIn_5+xSn₂O₁₆ was formed at 5 at% Ga-doped ITO. Moreover, the ITO lattice parameters decreased up to 40 at% Ga doping, since the ionic radius of Ga³⁺ is smaller than that of In³⁺. Furthermore, as the Ga concentration increased, the carrier concentration and mobility decreased and resistivity increased. These modifications are thought to result from an increasing quantity of the Ga_3-xIn_5+xSn₂O₁₆ s phase and the corresponding resistivity increase, both of which occur as a function of increasing Ga concentration.