Han Kyu-Bum, Chong Su Kong, Oliynyk Anton O, Nagaoka Akira, Petryk Suzanne, Scarpulla Michael A, Deshpande Vikram V, Sparks Taylor D
Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah, 84112, USA.
Department of Physics and Astronomy, University of Utah, Salt Lake City, Utah, 84112, USA.
Sci Rep. 2018 Nov 23;8(1):17290. doi: 10.1038/s41598-018-35674-z.
Despite numerous studies on three-dimensional topological insulators (3D TIs), the controlled growth of high quality (bulk-insulating and high mobility) TIs remains a challenging subject. This study investigates the role of growth methods on the synthesis of single crystal stoichiometric BiSbTeSe (BSTS). Three types of BSTS samples are prepared using three different methods, namely melting growth (MG), Bridgman growth (BG) and two-step melting-Bridgman growth (MBG). Our results show that the crystal quality of the BSTS depend strongly on the growth method. Crystal structure and composition analyses suggest a better homogeneity and highly-ordered crystal structure in BSTS grown by MBG method. This correlates well to sample electrical transport properties, where a substantial improvement in surface mobility is observed in MBG BSTS devices. The enhancement in crystal quality and mobility allow the observation of well-developed quantum Hall effect at low magnetic field.
