Revisiting the van der Waals Epitaxy in the Case of (Bi0.4Sb0.6)2Te3 Thin Films on Dissimilar Substrates

Liesbeth Mulder; Daan H Wielens; Yorick A Birkhölzer; Alexander Brinkman; Omar Concepción

doi:10.3390/nano12111790

Revisiting the van der Waals Epitaxy in the Case of (Bi_0.4Sb_0.6)₂Te₃ Thin Films on Dissimilar Substrates

Nanomaterials (Basel). 2022 May 24;12(11):1790. doi: 10.3390/nano12111790.

Authors

Liesbeth Mulder¹, Daan H Wielens¹, Yorick A Birkhölzer¹, Alexander Brinkman¹, Omar Concepción¹

Affiliation

¹ MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands.

Abstract

Ultrathin films of the ternary topological insulator (Bi0.4Sb0.6)2Te3 are fabricated by molecular beam epitaxy. Although it is generally assumed that the ternary topological insulator tellurides grow by van der Waals epitaxy, our results show that the influence of the substrate is substantial and governs the formation of defects, mosaicity, and twin domains. For this comparative study, InP (111)A, Al2O3 (001), and SrTiO3 (111) substrates were selected. While the films deposited on lattice-matched InP (111)A show van der Waals epitaxial relations, our results point to a quasi-van der Waals epitaxy for the films grown on substrates with a larger lattice mismatch.

Keywords: (Bi1−xSbx)2Te3; molecular beam epitaxy; thin films; topological insulators; van der Waals epitaxy.

Grants and funding

This work is financially supported by the Netherlands Organisation for Scientific Research (NWO) through a VICI grant and by Forschungszentrum Jülich.