title: Complex Nanotwin Substructure of an Asymmetric Σ9 Tilt Grain Boundary in a Silicon Polycrystal.
abstract: Grain boundaries in materials have substantial influences on device properties, for instance on mechanical stability or electronic minority carrier lifetime in multicrystalline silicon solar cells. This applies especially to asymmetric, less ordered or faceted interface portions. Here, we present the complex atomic interface structure of an asymmetric Σ9 tilt grain boundary in silicon, observed by high resolution scanning transmission electron microscopy (HR-STEM) and explained by atomistic modeling and computer simulation. Structural optimization of interface models for the asymmetric Σ9 and related symmetrical Σ9 and Σ3 tilt grain boundaries, by means of molecular-statics simulations with empirical silicon potentials in combination with first-principles calculations, results in a faceted asymmetric interface structure, whose grain-boundary energy is so low that it is likely to exist. The simulated local atomic structures match the observed HR-STEM images very well.
authors.affiliation: Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straβe 1, 40237 Düsseldorf, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Stoffers
authors.affiliation: Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstraße 11, 79108 Freiburg, Germany.|Karlsruher Institut für Technologie, Institut für Angewandte Materialien (IAM-CMS), Engelbert-Arnold-Straße 4, 76131 Karlsruhe, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Ziebarth
authors.affiliation: Central Facility for Electron Microscopy, RWTH Aachen University, 52074 Aachen, Germany.|Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Barthel
authors.affiliation: Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straβe 1, 40237 Düsseldorf, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Cojocaru-Mirédin
authors.affiliation: Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstraße 11, 79108 Freiburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Elsässer
authors.affiliation: Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Straβe 1, 40237 Düsseldorf, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Raabe