title: Evolution of Irradiation-Induced Vacancy Defects in Boron Nitride Nanotubes.
abstract: Irradiation-induced vacancy defects in multiwalled (MW) boron nitride nanotubes (BNNTs) are investigated via in situ high-resolution transmission electron microscope operated at 80 kV, with a homogeneous distribution of electron beam intensity. During the irradiation triangle-shaped vacancy defects are gradually generated in MW BNNTs under a mediate electron current density (30 A cm(-2)), by knocking the B atoms out. The vacancy defects grow along a well-defined direction within a wall at the early stage as a result of the curvature induced lattice strain, and then develop wall by wall. The orientation or the growth direction of the vacancy defects can be used to identify the chirality of an individual wall. With increasing electron current density, the shape of the irradiation-induced vacancy defects changes from regular triangle to irregular polygon.
authors.affiliation: Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
authors.forename: Guangming
authors.initials: G
authors.lastname: Cheng
authors.affiliation: Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
authors.forename: Shanshan
authors.initials: S
authors.lastname: Yao
authors.affiliation: Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
authors.forename: Xiahan
authors.initials: X
authors.lastname: Sang
authors.affiliation: Department of Physics, Michigan Technological University, Houghton, MI, 49931, USA.
authors.forename: Boyi
authors.initials: B
authors.lastname: Hao
authors.affiliation: Department of Physics, Michigan Technological University, Houghton, MI, 49931, USA.
authors.forename: Dongyan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Physics, Michigan Technological University, Houghton, MI, 49931, USA.
authors.forename: Yoke Khin
authors.initials: YK
authors.lastname: Yap
authors.affiliation: Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695, USA.|Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhu
keywords: TEM; boron nitride, nanotubes; electron irradiation; irradiation-induced defects; vacancy defects