Effect of ZnO addition in In2O3 ceramics: defect chemistry and sintering behavior

In this study, the solid solution feature of Zn2+ in In2O3 was studied as functions of Zn content and sintering atmosphere. The solubility limit of Zn in In2O3 is close to 1 at.% when IZO (indium zinc oxide) was sintered in oxygen atmosphere. Sintering in nitrogen decreased the solubility limit less than 1 at.%. On the basis of lattice constant, microstructure and electrical characteristics, it was found that Zn forms a substitutional solid solution with In2O3 up to 0.5 at.% then changed to interstitial solid solution beyond 0.5 at.% when samples were sintered in oxygen. On the contrary, Zn formed interstitial solid solution when the samples were sintered in nitrogen. It was discussed with defect chemistry on the basis of the structural unstable of In2O3.