Two-dimensional bismuth-rich nanosheets through the evaporative thinning of Se-doped Bi2Te3

Eve D. Hanson, Fengyuan Shi, Thomas C. Chasapis, Mercouri G Kanatzidis, Vinayak P. Dravid

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

High bulk conductance obscures the behavior of surface states in the prototypical topological insulators Bi2Te3 and Bi2Se3. However, ternary phases of Bi2Te3-ySey with balanced donor and acceptor levels may lead to large bulk resistivity, allowing for the observation of the surface states. Additionally, the contribution of the bulk conductance may be further suppressed by nanostructuring, increasing the surface-to-volume ratio. Herein we report the synthesis of a ternary tetradymite newly confined to two dimensions. Ultra-thin large-area stable nanosheets were fabricated via evaporative thinning of a Bi2Te2.9Se0.1 original phase. Owing to vapor pressure differences, a compositional shift to a final Bi-rich phase is observed. The Se/Te ratio of the nanosheet increases tenfold, due to the higher stability of the Bi-Se bonds. Hexagonal crystal symmetry is maintained despite dramatic changes in thickness and stoichiometry. Given that small variations in stoichiometry of this ternary system can incur large changes in carrier concentration and switch majority carrier type, the large compositional shifts found in this case imply that compositional analysis of similar CVD and PVD grown materials is critical to correctly interpret topological insulator performance. Further, the characterization techniques deployed, including STEM-EDS and ToF-SIMS, serve as a case study in determining such compositional shifts in two-dimensional form.

Original languageEnglish
Pages (from-to)138-144
Number of pages7
JournalJournal of Crystal Growth
Volume436
DOIs
Publication statusPublished - Feb 15 2016

Fingerprint

Bismuth
Nanosheets
Surface states
Stoichiometry
bismuth
Strategic materials
stoichiometry
shift
Crystal symmetry
Physical vapor deposition
Ternary systems
Secondary ion mass spectrometry
Vapor pressure
insulators
Carrier concentration
Energy dispersive spectroscopy
Chemical vapor deposition
majority carriers
Switches
ternary systems

Keywords

  • A1. Solid solutions
  • A3. Evaporative thinning
  • A3. Physical vapor deposition processes
  • B1. Nanomaterials
  • B2. Semiconducting ternary compounds
  • B2. Topological insulators

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Chemistry
  • Inorganic Chemistry

Cite this

Two-dimensional bismuth-rich nanosheets through the evaporative thinning of Se-doped Bi2Te3 . / Hanson, Eve D.; Shi, Fengyuan; Chasapis, Thomas C.; Kanatzidis, Mercouri G; Dravid, Vinayak P.

In: Journal of Crystal Growth, Vol. 436, 15.02.2016, p. 138-144.

Research output: Contribution to journalArticle

Hanson, Eve D. ; Shi, Fengyuan ; Chasapis, Thomas C. ; Kanatzidis, Mercouri G ; Dravid, Vinayak P. / Two-dimensional bismuth-rich nanosheets through the evaporative thinning of Se-doped Bi2Te3 In: Journal of Crystal Growth. 2016 ; Vol. 436. pp. 138-144.
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