title: Atomic-scale disproportionation in amorphous silicon monoxide.
abstract: Solid silicon monoxide is an amorphous material which has been commercialized for many functional applications. However, the amorphous structure of silicon monoxide is a long-standing question because of the uncommon valence state of silicon in the oxide. It has been deduced that amorphous silicon monoxide undergoes an unusual disproportionation by forming silicon- and silicon-dioxide-like regions. Nevertheless, the direct experimental observation is still missing. Here we report the amorphous structure characterized by angstrom-beam electron diffraction, supplemented by synchrotron X-ray scattering and computer simulations. In addition to the theoretically predicted amorphous silicon and silicon-dioxide clusters, suboxide-type tetrahedral coordinates are detected by angstrom-beam electron diffraction at silicon/silicon-dioxide interfaces, which provides compelling experimental evidence on the atomic-scale disproportionation of amorphous silicon monoxide. Eventually we develop a heterostructure model of the disproportionated silicon monoxide which well explains the distinctive structure and properties of the amorphous material.
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hirata
authors.affiliation: Quantum Beam Unit, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.|Information Integrated Materials Research Unit, Research Center for Information Integrated Materials, NIMS, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan.|Division of Research &Utilization, Japan Synchrotron Radiation Research Institute, Hyogo 679-5198, Japan.|Schools of Materials Science, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa 923-1291, Japan.|JST, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kohara
authors.affiliation: Device-functional Analysis Department, NISSAN ARC Ltd., 1 Natsushima, Yokosuka 237-0061, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Asada
authors.affiliation: Device-functional Analysis Department, NISSAN ARC Ltd., 1 Natsushima, Yokosuka 237-0061, Japan.
authors.forename: Masazumi
authors.initials: M
authors.lastname: Arao
authors.affiliation: Device-functional Analysis Department, NISSAN ARC Ltd., 1 Natsushima, Yokosuka 237-0061, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Yogi
authors.affiliation: Device-functional Analysis Department, NISSAN ARC Ltd., 1 Natsushima, Yokosuka 237-0061, Japan.
authors.forename: Hideto
authors.initials: H
authors.lastname: Imai
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.|State Key Laboratory of Metal Matrix Composites and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
authors.forename: Yongwen
authors.initials: Y
authors.lastname: Tan
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Takeshi
authors.identifier: http://orcid.org/0000-0002-2318-0433
authors.initials: T
authors.lastname: Fujita
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.|State Key Laboratory of Metal Matrix Composites and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.|JST, CREST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
authors.forename: Mingwei
authors.initials: M
authors.lastname: Chen