title: Probing of 2 dimensional confinement-induced structural transitions in amorphous oxide thin film.
abstract: Whereas the atomic structure of surface of crystals is known to be distinct from that of bulk, experimental evidence for thickness-induced structural transitions in amorphous oxides is lacking. We report the NMR result for amorphous alumina with varying thickness from bulk up to 5 nm, revealing the nature of structural transitions near amorphous oxide surfaces/interfaces. The coordination environments in the confined amorphous alumina thin film are distinct from those of bulk, highlighted by a decrease in the fractions of high-energy clusters (and thus the degree of disorder) with thickness. The result implies that a wide range of variations in amorphous structures may be identified by controlling its dimensionality.
authors.affiliation: Laboratory of Physics and Chemistry of Earth Materials, School of Earth and Environmental Sciences, Seoul National University, Seoul, 151-742 Korea.
authors.forename: Sung Keun
authors.initials: SK
authors.lastname: Lee
authors.affiliation: National Nanofab Center, Korean Advanced Institute of Science and Technology, Daejeon 305-806, Korea.
authors.forename: Chi Won
authors.initials: CW
authors.lastname: Ahn