title: Embedding Ba Monolayers and Bilayers in Boron Carbide Nanowires.
abstract: Aberration corrected high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) was employed to study the distribution of barium atoms on the surfaces and in the interiors of boron carbide based nanowires. Barium based dopants, which were used to control the crystal growth, adsorbed to the surfaces of the boron-rich crystals in the form of nanometer-thick surficial films (a type of surface complexion). During the crystal growth, these dopant-based surface complexions became embedded inside the single crystalline segments of fivefold boron-rich nanowires collectively, where they were converted to more ordered monolayer and bilayer modified complexions. Another form of bilayer complexion stabilized at stacking faults has also been identified. Numerous previous works suggested that dopants/impurities tended to segregate at the stacking faults or twinned boundaries. In contrast, our study revealed the previously-unrecognized possibility of incorporating dopants and impurities inside an otherwise perfect crystal without the association to any twin boundary or stacking fault. Moreover, we revealed the amount of barium dopants incorporated was non-equilibrium and far beyond the bulk solubility, which might lead to unique properties.
authors.affiliation: Beijing National Center for Electron Microscopy, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084, China.|Center for Advanced Materials and Nanotechnology, Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States.
authors.forename: Zhiyang
authors.initials: Z
authors.lastname: Yu
authors.affiliation: Department of NanoEngineering, Program of Materials Science and Engineering, University of California, San Diego, California 92093, United States.
authors.forename: Jian
authors.initials: J
authors.lastname: Luo
authors.affiliation: Department of Mechanical Engineering &Mechanics, Lehigh University, Bethlehem, Pennsylvania 18015, United States.
authors.forename: Baiou
authors.initials: B
authors.lastname: Shi
authors.affiliation: Beijing National Center for Electron Microscopy, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084, China.
authors.forename: Jiong
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Center for Advanced Materials and Nanotechnology, Department of Materials Science and Engineering, Lehigh University, Bethlehem, Pennsylvania 18015, United States.
authors.forename: Martin P
authors.initials: MP
authors.lastname: Harmer
authors.affiliation: Beijing National Center for Electron Microscopy, School of Materials Science and Engineering, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Materials (MOE), Tsinghua University, Beijing 100084, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhu