Review of 3D topological insulator thin-film growth by molecular beam epitaxy and potential applications

Thin films of V-VI compound semiconductors (Bi2Se3, Bi2Te3 and Sb2Te3) have been synthesized recently as three-dimensional topological insulators (TIs). Although these materials have been used as thermoelectric materials for many years, for future studies and applications of the topological surface states, a major bottleneck remains the lack of high-quality bulk materials that have very few defects and the Fermi level can be moved to inside the bulk bandgap. In this paper, we review the use of molecular beam epitaxy (MBE) technique to achieve high-quality TI materials. Furthermore, the use of layered growth in MBE affords us the fabrication of heterostructures, such as quantum wells and superlattices. Thus, it may further enable additional studies and applications, similar to those of conventional semiconductor heterostructures but with the novel properties of TI. We explore the growth mechanism, providing a detail discussion on the growth parameters of thin-film synthesis by MBE. Then we discuss more complex cases, such as functional doping, heterostructures and superlattices. Potential new properties in such quantum structures are discussed. Finally, we give an outlook on this material system for both fundamental studies and applications. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim