| 1. |
- Andzane, J., et al.
(författare)
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Catalyst-free vapour-solid technique for deposition of Bi2Te3 and Bi2Se3 nanowires/nanobelts with topological insulator properties
- 2015
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 7:38, s. 15935-15944
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Tidskriftsartikel (refereegranskat)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 N-2 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.
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| 2. |
- Kunakova, Gunta, et al.
(författare)
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Bulk-free topological insulator Bi2Se3 nanoribbons with magnetotransport signatures of Dirac surface states
- 2018
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3372 .- 2040-3364. ; 10:41, s. 19595-19602
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Tidskriftsartikel (refereegranskat)abstract
- © 2018 The Royal Society of Chemistry. Many applications of topological insulators (TIs) as well as new phenomena require devices with reduced dimensions. While much progress has been made to realize thin films of TIs with low bulk carrier densities, nanostructures have not yet been reported with similar properties, despite the fact that reduced dimensions should help diminish the contributions from bulk carriers. Here we demonstrate that Bi2Se3 nanoribbons, grown by a simple catalyst-free physical-vapour deposition, have inherently low bulk carrier densities, and can be further made bulk-free by thickness reduction, thus revealing the high mobility topological surface states. Magnetotransport and Hall conductance measurements, in single nanoribbons, show that at thicknesses below 30 nm, the bulk transport is completely suppressed which is supported by self-consistent band-bending calculations. The results highlight the importance of material growth and geometrical confinement to properly exploit the unique properties of topological surface states.
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