title: Origin of the apparent delocalization of the conduction band in a high-mobility amorphous semiconductor.
abstract: In this paper, we show that the apparent delocalization of the conduction band reported from first-principles simulations for the high-mobility amorphous oxide semiconductor [Formula: see text] (a-IGZO) is an artifact induced by the periodic conditions imposed to the model. Given a sufficiently large unit-cell dimension (over 40 Å), the conduction band becomes localized. Such a model size is up to four times the size of commonly used models for the study of a-IGZO. This finding challenges the analyses done so far on the nature of the defects and on the interpretation of numerous electrical measurements. In particular, we re-interpret the meaning of the computed effective mass reported so far in literature. Our finding also applies to materials such as SiZnSnO, ZnSnO, InZnSnO, In2O3or InAlZnO4whose models have been reported to display a fully delocalized conduction band in the amorphous phase.
authors.affiliation: KU Leuven, ESAT, B-3001 Leuven, Belgium. IMEC, Kapeldreef 75, B-3001 Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: de Jamblinne de Meux
authors.forename: G
authors.initials: G
authors.lastname: Pourtois
authors.forename: J
authors.initials: J
authors.lastname: Genoe
authors.forename: P
authors.initials: P
authors.lastname: Heremans