Dresden 2026 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 4: Thin Film Properties II

DS 4.2: Vortrag

Montag, 9. März 2026, 16:45–17:00, REC/C213

high-quality Bi₂Te₃ TI thin films on [0001]-oriented sapphire substrate grown by MBE — •Ismet Gelen, Ahmet Yagmur, Luke Benson, and Satoshi Sasaki — School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, UK

Over the past decades, topological insulators (TIs) have attracted great attention for their exotic property of being insulating in the bulk while conductive on the surfaces through topological surface states [1], offering promising prospects for future spintronic technologies [2]. Molecular beam epitaxy (MBE) growth method is very important to produce high-quality epitaxial thin film TIs samples. However, producing a high-quality thin film requires careful consideration of substrate preference, growth temperature, and growth rate. This study focuses on the systematic growth of high-quality Bi₂Te₃ TI thin films on a sapphire [0001] substrate with minimal lattice mismatch. We found that growth temperature has a big influence on the surface morphology, which can lead to small or large triangular terraces. When temperature is too low it can create pillars when it is too high it creates defects/holes in films. We will report our optimization of the Bi₂Te₃ growth in terms of X-ray reflectivity/diffraction, atomic force microscopy, Raman spectroscopy, and magnetotransport properties by measuring standard Hall-bar type devices at low temperatures. Finally, we obtain films with large grain size without defects/pillars, and with high mobility and low carrier density.

[1] Li, Y., et al. (2022). ACS Nano, 16(6), 9953-9959. [2] Hasan, M. Z., et al. (2010). Reviews of Modern Physics, 82(4), 3045-3067.

Keywords: topological insulators; thin films; magnetotransport; atomic force microscopy; X-ray diffraction