The microscope is equipped with an analytical high-resolution pole piece, which can realize a point resolution of 0.23 nm, a lattice resolution of 0.14 nm, and a specimen tilting range of ±30° in both X and Y directions. A JEOL double-tilt holder was used to realize the wide angle of tilting. It is worth pointing out that the 60° in total tilting range is comparable to or even wider than that of the most microscopes researchers used to study 1D nanostructures. The operation acceleration voltage used for this study was 200 kV. Software packages CrystalMaker® and SingleCrystal™, Oxfordshire, UK, were used to construct, display, and manipulate three-dimensional models of boron carbide unit cell and MAPK inhibitor nanowires,

as well as to simulate corresponding VS-4718 mw selleck screening library electron diffraction patterns. All crystallographic indexes used in this paper are expressed in the rhombohedral notation for convenience of discussion (see Additional file 1 for conversion between the rhombohedral notation and the hexagonal notation). Results and discussion ‘Hidden’ defects The existence of ‘hidden’ defects Our previous work [22] showed that 100-type planar defects such as stacking faults and twins of variable width are commonly observed from as-synthesized boron carbide nanowires. The planar defects can be further categorized into transverse faults and axial faults, depending on the geometrical relation between the planar defects

and the preferred growth direction of a nanowire. Figure 1a,b shows the typical HRTEM images of a TF nanowire with planar defects perpendicular to its preferred growth direction and an AF nanowire with planar defects parallel to its preferred growth direction, respectively. Figure 1 Typical TEM results. Results of (a) a TF nanowire whose preferred growth

direction is perpendicular to (001) planar defects and (b) an AF nanowire whose preferred growth direction is parallel to (001) planar defects. Results of a nanowire whose planar defects are (c) invisible along the [110] zone axis, but (d) clearly revealed after titling to the [010] zone axis. Results of (e) a nanowire whose planar defects (f) are invisible after a full range of tilting examination. The same nanowire (g) was picked up and repositioned by a micromanipulator. 17-DMAG (Alvespimycin) HCl Planar defects (h) are now clearly shown. As briefly pointed out in our previous report [22], wide angle of tilting during TEM examination is needed to reveal the existence of planar defects in as-synthesized boron carbide nanowires. Figure 1c shows the TEM results of a nanowire that seems to be planar defect-free due to the lack of modulated contrast in the image and streaks in the electron diffraction pattern. However, after tilting the nanowire to a different zone axis, all ‘hidden’ planar defects emerged as clearly shown in Figure 1d, revealing a TF nanowire. This example undoubtedly demonstrates that one cannot conclude that a nanowire is planar defect-free based on TEM results obtained from one single viewing direction.