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.

Identification of interfacial defects in the layered structure of a chalcopyrite compound

“…The cause of this low performance is not understood.Here, a single crystal grown from 1 mol % Cu-deficient melt was studied by using atomic resolution highangle annular dark-field (HAADF) scanning transmission electron microscopy (STEM) and electron dispersive spectroscopy (EDS) (no beam damage issue). [3,4] Figure 1 shows that the CuInS2 crystal has a lamellar structure, taken in the ⟨11̅ 0⟩ direction. The lamellae are alternating pseudotwins that form a herringbone pattern (Fig.…”

Interaction of dislocations with twinning boundary in bi-twinned metallic nanowires

“…Note that the viewing direction in Fig. 1c,d is from the [1][2][3][4][5][6][7][8][9][10] zone axis as marked by the orange arrow in the inset in Fig. 1a.…”

“…Figure1shows the stress-strain responses and snapshots of microstructure evolution during typical loading-unloading cycles of a bi-twinned Ag NW with or without a holding step. Note that the viewing direction in Fig.1c,d is from the[1][2][3][4][5][6][7][8][9][10] zone axis as marked by the orange arrow in the inset in Fig.1a. As a partial dislocation (marked by A in Fig.4 c-ii) came out during loading (with the applied stress, 1.46 GPa, slightly over the yield strength, 1.41 GPa), we immediately started unloading the NW by decreasing the applied force.…”

Tensile detwinning in bi-twinned metallic nanowires

“…1d. Note that there is no obvious change of the dimension along [1][2][3][4][5][6][7][8][9][10] orientation but a large size shrinkage along the direction perpendicular to [1][2][3][4][5][6][7][8][9][10]…”