Modulation effect on the effective mass of free carriers induced by multicomponent elements in In2O3-based transparent conducting oxides

摘要

Motivated by extensive investigations on the In2O3-based multicomponent transparent conducting oxides (TCOs), we want to know the carrier transport properties in these systems and how they evolve with adjusting of geometric structure and constituent elements. Guided by the empirical minimum effective mass physics, we select nine impurities M (M = Sn, Zn, Cd, Hg, Mn, Ni, Co, Ga and Ge) to tune the effective mass (m*) of In2O3-based TCOs. By means of systematic theoretical investigations, we find that in impurity M isolated or corporately doped In2O3 materials, the substitutional position for dopant M is determined by the charge state. Codoping Sn and other eight impurities into In2O3 (to form IMTO) is an effective strategy to reduce the indium content in In2O3-based TCOs materials. For the recognized n-type carrier contributor, namely, V-o defect, it induce spatial localization and orbital localization effects in electronic structures and thus enlarge m*, which are caused by the large lattice distortion and complicated orbital wavefunction hybridizations. However, for IMTO:V-o (M = Zn, Ga and Hg) systems, both localization effects are weakened, leading to a decrease of m*. It even reduces by half value for In-Hg-Sn-O:V-o systems. This systematic work in In2O3-based materials may be helpful in designing of a new range of high performance TCOs. (C) 2017 Elsevier B.V. All rights reserved.