Facile synthesis of high-crystalline Bi2Se3 nanoribbons without Se vacancies and their properties

The avoiding of impurities and high intrinsic defects in 3D TIs has brought great challenges to chemists and materials scientists. In this paper, a feasible method of vapor-phase deposition was proposed for preparing high-performance Bi2Se3 nanoribbons, which can effectively avoid Se vacancies without introducing new impurity species. It was found that the length and density of Bi2Se3 nanoribbons can be controlled by adjusting the heating temperature. Importantly, the growth temperature which has often been ignored plays a key role in the stoichiometric ratio and crystallinity of the nanostructures. We obtained a large area of high-crystalline Bi2Se3 nanoribbons with standard stoichiometric ratio and flattened surface just through changing the two temperatures. The properties of the synthesized nanoribbons with different stoichiometric ratios have been investigated systematically. The blueshift of the Raman modes is probably attributed to the decrease in Se vacancy defects which strengthens the electron-phonon interaction between atoms. While the band gap shows a redshift behavior with the decrease in Se vacancy defects speculated from the absorption spectra, this facile method can be applied to synthesize other 3D TIs with standard stoichiometric ratio without introducing new impurities, which could lay a strong foundation toward large-scale production for practical applications of 3D TIs.