Transmission electron microscopy evidence of the defect structure in Si nanowires synthesized by laser ablation

Using electron diffraction and high-resolution transmission electron microscopy (HRTEM), we have characterized the microstructure of the Si nanowires synthesized by laser ablation at high temperature. Unlike the Si whiskers, the nanowires are extremely long and highly curved with a typical diameter of about 20 nm. High density of stacking faults and twins have been observed in the Si core of the nanowires. The {111} surfaces of the Si crystals are parallel to the axes of the nanowires. As identified by electron diffraction and HRTEM, the nanowire axes are generally along the 〈211〉 direction. The nanowires bend gradually via a high density of defects and kink abruptly along the equivalent directions of 〈211〉.