Multi-component transparent conducting oxides: Progress in materials modelling

Transparent conducting oxides (TCOs) play an essential role in modern optoelectronic devices through their combination of electrical conductivity and optical transparency. We review recent progress in our understanding of multi-component TCOs formed from solid solutions of ZnO, In₂O ₃, Ga₂O₃ and Al₂O₃, with a particular emphasis on the contributions of materials modelling, primarily based on density functional theory. In particular, we highlight three major results from our work: (i)the fundamental principles governing the crystal structures of multi-component oxide structures including (In₂O ₃)(ZnO)_n and (In₂O₃) _m(Ga₂O₃)_l(ZnO)_n; (ii)the relationship between elemental composition and optical and electrical behaviour, including valence band alignments; (iii)the high performance of amorphous oxide semiconductors. On the basis of these advances, the challenge of the rational design of novel electroceramic materials is discussed.