Origin of electronic and optical trends in ternary ${\text{In}}_{2}{\text{O}}_{3}{(\text{ZnO})}_{n}$ transparent conducting oxides $(n=1,3,5)$: Hybrid density functional theory calculations

Origin of electronic and optical trends in ternary ${In}_{2} O_{3} {(ZnO)}_{n}$ transparent conducting oxides $(n = 1, 3, 5)$ : Hybrid density functional theory calculations

Aron Walsh, Juarez L. F. Da Silva, Yanfa Yan, M. M. Al-Jassim, and Su-Huai Wei

Phys. Rev. B 79, 073105 – Published 26 February 2009

Abstract

Ternary oxides formed from zinc and indium have demonstrated potential for commercial optoelectronic applications. We present state-of-the-art hybrid density functional theory calculations for Zn-poor and Zn-rich compositions of the crystalline ${In}_{2} O_{3} {(ZnO)}_{n}$ compounds. We reveal the origin of the redshift in optical transitions compared to the two component oxides: symmetry forbidden band-edge transitions in ${In}_{2} O_{3}$ are overcome on formation of the superlattices, with Zn-O contributions to the top of the valence band. Increasing $n$ results in the localization of the conduction-band minimum on the In-O networks. This enhanced localization explains why Zn-poor compounds (lower $n$ ) exhibit optimal conductivity.