Epitaxial growth and electronic properties of quasi-free-standing rhombohedral <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>WSe</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:mrow> </mml:math> bilayers on cub
Rhombohedral-stacked transition metal dichalcogenides (TMDs) break inversion symmetry between adjacent layers, giving rise to an intrinsic out-of-plane ferroelectric polarization. Controlling the formation of this stacking polytype is therefore essential for harnessing ferroelectric effects in two-dimensional materials. In this work, we demonstrate the epitaxial growth of rhombohedral bilayer tungsten diselenide (3R-${\mathrm{WSe}}_{2}$) on a cubic W(110) single crystal by molecular beam epitaxy. We show that selenium passivation of the substrate is key to enable a quasi-van der Waals epitaxy, effectively suppressing strong interfacial bonding and promoting the growth of quasi free-standing bilayer films. The 3R stacking order is confirmed through a combination of Raman spectroscopy and high-resolution angle-resolved photoemission spectroscopy (ARPES), supported by density functional theory (DFT) calculations. ARPES and DFT reveals an indirect-gap electronic structure with the valence-band maximum at the \ensuremath{\Gamma} point, as well as a pronounced spin-orbit-driven splitting of $520\ifmmode\pm\else\textpm\fi{}20$ meV at the K point. Analysis of the measured dispersions yields hole effective masses of $0.46\ifmmode\pm\else\textpm\fi{}0.04\phantom{\rule{0.16em}{0ex}}{m}_{e}$ and $0.75\ifmmode\pm\else\textpm\fi{}0.06\phantom{\rule{0.16em}{0ex}}{m}_{e}$ for the upper and lower valence bands at K point, respectively. These results establish a robust route for synthesizing quasi-free-standing 3R-${\mathrm{WSe}}_{2}$ and provide a platform for exploring the electronic, optical, and ferroelectric functionalities that emerge from inversion-symmetry breaking in layered TMDs. Our findings further highlight the potential of cubic substrates for deterministic fabrication of rhombohedral TMD heterostructures and ferroelectric devices at the nanoscale.
Authors
- Abdelkarim Ouerghi (ORCID: https://orcid.org/0000-0002-1898-2765)
- Iann C. Gerber (ORCID: https://orcid.org/0000-0001-5091-2655)
- Meryem Bouaziz
- Julien Chaste (ORCID: https://orcid.org/0000-0001-8384-0133)
- F. Oehler
- Eva Desgué (ORCID: https://orcid.org/0009-0009-6078-1551)
- Pierre Legagneux
- François Bertarn
- Niels Chapuis
Institutions
- Université Fédérale de Toulouse Midi-Pyrénées (FR)
- Université Paris-Saclay (FR)
- Synchrotron soleil (FR)
- Thales (Australia) (AU)
- Centre de Nanosciences et de Nanotechnologies (FR)
- Laboratoire de Physique et Chimie des Nano-Objets (FR)
Publication Details
- Journal
- Physical Review Materials
- Published
- 2026-04-13
- DOI
- https://doi.org/10.1103/xs47-7hky
- Primary Topic
- 2D Materials and Applications
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- Agence Nationale de la Recherche
- Grand Équipement National De Calcul Intensif