High-resolution electron microscopy of twist and general grain boundaries

High-resolution imaging of atomic structures of twist and general grain bou ndaries (GBs) is reported in samples prepared by a thin-film technique in w hich [011] and [001] oriented An grains are epitaxially grown side by side, allowing the investigation of a wide range of GB geometries. GBs with tilt as well as twist components typically have structural modulations along th e interface and often show a surprising amount of coherence between lattice planes crossing the interface. The [110], 90 degrees symmetric twist GB do es not remain planar, but reconstructs into atomic-scale microfacets.