Growth, Structure, and Electronic Properties of Epitaxial Bismuth Telluride Topological Insulator Films on BaF2 (111) Substrates
Sprache des Titels:
Epitaxial growth of topological insulator
bismuth telluride by molecular beam epitaxy onto BaF2
(111) substrates is studied using Bi2Te3 and Te as source
materials. By changing the beam flux composition, different
stoichiometric phases are obtained, resulting in high quality
Bi2Te3 and Bi1Te1 epilayers as shown by Raman spectroscopy
and high-resolution X-ray diffraction. From X-ray reciprocal
space mapping, the residual strain, as well as size of coherently
scattering domains are deduced. The Raman modes for the
two different phases are identified and the dielectric functions
derived from spectroscopic ellipsometry investigations.
Angular resolved photoemission reveals topologically protected
surface states of the Bi2Te3 epilayers. Thus, BaF2 is a
perfectly suited substrate material for the bismuth telluride compounds.