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O: Fachverband Oberflächenphysik
O 14: 2D Materials Beyond Graphene: Growth, Structure and Substrate Interaction (joint session O/HL)
O 14.11: Talk
Monday, March 17, 2025, 17:30–17:45, H11
In-situ growth and characterization of 2D TaSe2 on Au(111) — •Cathy Sulaiman1, Lars Buß1, Raquel Sánchez-Barquilla1, Jens Falta2, and Jan Ingo Flege1 — 1Applied Physics and Semiconductor Spectroscopy, BTU Cottbus-Senftenberg, Cottbus, Germany — 2Institute for Solid State Physics, University of Bremen, Bremen, Germany
Group V dichalcogenides such as TaX2 (X = S, Se, T) have extensively been investigated in recent decades due to their diverse electron correlation effects, including the occurrence of charge density waves and Mott-Hubbard transitions. In 2D, two polytypes, 1T and 1H, exist, which exhibit distinct properties, making selective growth of each polytype crucial. Using low-energy electron microscopy (LEEM), we have successfully observed the growth of two TaSe2 phases on Au(111) in situ after the co-deposition of Ta and Se. At elevated temperature, micron-sized, triangle-shaped islands with bright contrast nucleate first and grow at a higher rate. However, this phase turns out to be meta-stable as it suddenly transitions into a more stable phase (with dark contrast) and continues to grow at a reduced rate. Low-energy electron diffraction shows the presence of TaSe2; bandstructure-sensitive I(V)-LEEM analysis reveals substantial differences in electron reflectivity between both phases. A comparison with TaS2 suggests that the metastable and stable phases are 1T- and 1H-TaSe2, respectively.
Keywords: TMDC; LEEM; LEED