Growth, Structure, and Electronic Properties of Epitaxial Bismuth Telluride Topological Insulator Films on BaF2 (111) Substrates

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• 作者：O. Caha ; A. Dubroka ; J. Huml铆膷ek ; V. Hol媒 ; H. Steiner ; M. Ul-Hassan ; J. S谩nchez-Barriga ; O. Rader ; T. N. Stanislavchuk ; A. A. Sirenko ; G. Bauer ; G. Springholz
• 刊名：Crystal Growth & Design
• 出版年：2013
• 出版时间：August 7, 2013
• 年：2013
• 卷：13
• 期：8
• 页码：3365-3373
• 全文大小：544K
• 年卷期：v.13,no.8(August 7, 2013)
• ISSN：1528-7505

文摘

Epitaxial growth of topological insulator bismuth telluride by molecular beam epitaxy onto BaF<sub>2sub> (111) substrates is studied using Bi<sub>2sub>Te<sub>3sub> and Te as source materials. By changing the beam flux composition, different stoichiometric phases are obtained, resulting in high quality Bi<sub>2sub>Te<sub>3sub> and Bi<sub>1sub>Te<sub>1sub> 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 Bi<sub>2sub>Te<sub>3sub> epilayers. Thus, BaF<sub>2sub> is a perfectly suited substrate material for the bismuth telluride compounds.