Catalyst-free vapour–solid technique for deposition of Bi2Te3 and Bi2Se3 nanowires/nanobelts with topological insulator properties

Abstract

We present a simple two-stage vapour–solid synthesis method for the growth of bismuth chalcogenide (Bi₂Te₃, Bi₂Se₃) topological insulator nanowires/nanobelts by using Bi₂Se₃ or Bi₂Te₃ powders as source materials. During the first stage of the synthesis process nanoplateteles, serving as “catalysts” for further nanowire/nanobelt growth, are formed. At a second stage of the synthesis, the introduction of a N₂ flow at 35 Torr pressure in the chamber induces the formation of free standing nanowires/nanobelts. The synthesised nanostructures demonstrate a layered single-crystalline structure and Bi : Se and Bi : Te ratios 40 : 60 at% for both Bi₂Se₃ and Bi₂Te₃ nanowires/nanobelts. The presence of Shubnikov de Haas oscillations in the longitudinal magneto-resistance of the nanowires/nanobelts and their specific angular dependence confirms the existence of 2D topological surface states in the synthesised nanostructures.