Growth of single-crystalline bismuth antimony telluride nanoplates on the surface of nanoparticle thin films

Abstract

We have reported the growth of single-crystalline bismuth antimony telluride nanoplates on the surface of nanoparticle thin films using a simple sintering process. We prepared two types of bismuth antimony telluride thin films, one comprising nanoparticles and the other submicron particles. The nanoplates were found to grow only on thin films comprising nanoparticles. The structure, composition, and morphology of nanoplates were investigated by using X-ray diffractometry, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray analysis. The obtained nanoplates were of length 0.5–1μm and thickness less than 100nm. The atomic composition of the nanoplates was almost the same as that of the nanoparticles in the thin films. The nanoplates were found to be single crystalline, while the nanoparticles in the thin films were polycrystalline in nature. The growth of nanoplates on the surface of the thin films was due to the partial melting and evaporation of nanoparticles during the sintering process. As a result, the evaporated materials formed nuclei on the surface of the films, which then crystallized to form nanoplates.