Periodically twinned SiC nanowires

Abstract

Twinning has been recognized to be an important microstructural defect in nanoscale materials. Periodically twinned SiC nanowires were largely synthesized by the carbothermal reduction of a carbonaceous silica xerogel prepared from tetraethoxysilane and biphenyl with iron nitrate as an additive. The twinned β-SiC nanowires, with a hexagonal cross section, a diameter of 50-300 nm and a length of tens to hundreds of micrometers, feature a zigzag arrangement of periodically twinned segments with a rather uniform thickness along the entire growth length. Computer simulation has been used to generate three-dimensional atomic structures of the zigzag columnar twin structure by the stacking of hexagonal discs of {111} planes of SiC. A minimum surface energy and strain energy argument is proposed to explain the formation of periodic twins in the SiC nanowires. The thickness of the periodic twinned segments is found to be linearly proportional to the nanowire diameter, and a constant volume model is proposed to explain the relation.

Porous Nano-SiC as Thermal Insulator: Wisdom on Balancing Thermal Stability, High Strength and Low Thermal Conductivity

“…As a kind of stacking fault, twins are usually observed in nanostructures with a face-centered cubic (fcc) lattice. [23] The inset in Figure 1(b) also demonstrates the bright-field TEM image of S18 and corresponding high-resolution transmission microscopy (HRTEM) image and selected area electron diffraction (SAED) pattern taken along the direction of [110] zone axis. The twin boundary is the (111) plane and the side surface of each segment is the (111) plane.…”

Strengthening mechanisms and dislocation dynamics in twinned metal nanowires

“…7,8 Recently, twinned structures have also been reported in other semiconductor and ceramic materials, such as GaP, 9 ZnS, 10 and SiC. 11 Because twin boundaries (TBs) in these nano wires will strongly affect their mechanical and physical properties, it is of great signifi cance to investigate the details of twin structures and their roles in the nanowires. 12,13 This work focuses on revealing the strengthening mechanisms and dislocation dynamics due to twinning in copper nanowires.…”

Thermal Transport and Rectification Properties of Bamboo-Like SiC Polytypes Nanowires

“…Particularly in harsh conditions, SiC devices are much better than Si and GaAs devices [1]. Though SiC has hundreds of stable polytypes, the most commonly used ones are 3C-SiC, 4H-SiC, and 6H-SiC [2]. In recent years, there have been many experimental and theoretical efforts invested in the development of SiC nanostructures [3][4][5].…”