Elucidation of the Complex Structure of Nanoparticles Composed of Bismuth, Antimony, and Tellurium Using Scanning Transmission Electron Microscopy

Abstract

In this Article, we report on a study of the atomic structure of nanoparticles composed of bismuth, antimony, and tellurium with both wire and disk shape through use of the scanning transmission electron microscopy-high angle annular dark field detector technique. Recent advances in scanning transmission electron microscopy, such as aberration correction, have enabled a detailed structure analysis for materials with true atomic level resolution. Such ability is important for elucidating the underlying mechanisms, which give rise to the enhanced and novel properties displayed by nanoparticles. The atomic scale analysis of the particles revealed important insight into the nanoparticle structure. It was found that the nanowires are composed of both hexagonal tellurium and rhombohedral Bi2Te3 phases where the Bi2Te3 appears to have grown from the tips of the tellurium wires. The nanodiscs were found to be entirely rhombohedral in nature and were composed of both Bi2Te3 and Sb2Te3 phases with Bi2Te3 found at the particle center and Sb2Te3 appearing to subsequently grow at the periphery of the particles. The in-depth atomic structural characterization is expected to lead to a greater understanding of how to synthesize these thermoelectric type materials with more controllable properties such as size, shape, structure, and composition.