However, due to the sophistication of the TEM technique, sometimes, experimental artifacts could be erroneously interpreted or lead to controversy [6–10]. To date, most planar defect-related studies have

been focused on 1D nanostructures made of silicon, silicon carbide, III-V (e.g., GaAs, InP), or II-IV compounds (e.g., ZnO, CdSe) whose crystal structures are either cubic or hexagonal [8–15]. Boron carbide 1D nanostructures have attracted increasing attention in the last few years because of their potential applications in nanocomposites and thermoelectric energy conversion [16–25]. Most reported boron carbide 1D nanostructures were synthesized by carbothermal reduction or chemical vapor deposition at GSK461364 ic50 approximately GSK126 manufacturer 1,100°C [16–23]. Field emission [18, 23], photoluminescence [19], mechanical [21, 23], and thermal conductivity [22] properties of these 1D nanostructures were reported. However, due to the complicated rhombohedral crystal structure, detailed structural characterization especially on planar defects that could

greatly affect the properties of boron carbide 1D nanostructures has not yet gained enough attention, and the structure–property relations have not been established. In our previous study [22], about one hundred as-synthesized boron carbide nanowires were subjected to TEM study, during which each nanowire was examined throughout the full tilting range allowed by the configuration of our microscope. Approximately 75% examined nanowires were found to have planar defects, while the remaining 25% were planar defect-free-like. The defected nanowires were further categorized into two groups: transverse faults (TF) nanowires with planar defects perpendicular to the preferred growth direction of nanowires and axial faults (AF) nanowires with planar defects parallel to the preferred growth direction of nanowires. The determination of defects’ existence and fault orientations (TF or AF) within each nanowire was based on the characteristic features presented in TEM results, including modulated contrast in high-resolution TEM (HRTEM) images and

streaks in diffraction patterns. In this work, more extensive TEM examination and model simulation were performed to gain a deeper understanding MTMR9 of the nature of planar defects in the aforementioned boron carbide nanowires to answer two questions. (1) Do planar defect-free boron carbide nanowires really exist? Literature review shows that due to its relatively low stacking fault energy (75 mJ/m2) [26], planar defects have been frequently observed in bulk boron carbides independent of the synthesis Ispinesib in vivo methods [27–30]. It has also been reported that the density of planar defects decreases as the synthesis temperature increases [30]. However, the planar defects were still detectable by TEM from bulk samples synthesized at 2,100°C [30].