Dopability, intrinsic conductivity, and nonstoichiometry of transparent conducting oxides.

TLDR: The theoretical defect model for In(2)O(3) and ZnO finds that intrinsic acceptors have a high Delta H explaining high n-dopability, and the O vacancy V(O) has a metastable shallow state, explaining the paradoxical coexistence of coloration and conductivity.

Abstract: Existing defect models for ${\mathrm{In}}_{2}{\mathrm{O}}_{3}$ and ZnO are inconclusive about the origin of conductivity, nonstoichiometry, and coloration. We apply systematic corrections to first-principles calculated formation energies $\ensuremath{\Delta}H$, and validate our theoretical defect model against measured defect and carrier densities. We find that (i) intrinsic acceptors (``electron killers'') have a high $\ensuremath{\Delta}H$ explaining high $n$-dopability, (ii) intrinsic donors (``electron producers'') have either a high $\ensuremath{\Delta}H$ or deep levels, and do not cause equilibrium-stable conductivity, (iii) the O vacancy ${V}_{\mathrm{O}}$ has a low $\ensuremath{\Delta}H$ leading to O deficiency, and (iv) ${V}_{\mathrm{O}}$ has a metastable shallow state, explaining the paradoxical coexistence of coloration and conductivity.