Electronic properties of rhombohedrally stacked bilayer WSe2 obtained by chemical vapor deposition

Twisted layers of atomically thin two-dimensional materials support a broad range of quantum materials with engineered optical and transport properties. Transition metal dichalcogenides (TMDs) in the rhombohedral ($3R$, i.e., ${0}^{\ensuremath{\circ}}$ twist) crystal phase have been the focus of significant research interest in optical applications due to their particular broken inversion symmetry. Here, we report experimental and theoretical study of $\mathrm{W}{\mathrm{Se}}_{2}$ homobilayers obtained in stable $3R$ configuration by chemical vapor synthesis. We investigate the electronic and structural properties of these $3R\phantom{\rule{4pt}{0ex}}\mathrm{W}{\mathrm{Se}}_{2}$ bilayers with $3R$ stacking using micro-Raman spectroscopy, angle-resolved photoemission nanospectroscopy measurements, and density functional theory calculations. Our results demonstrate that $\mathrm{W}{\mathrm{Se}}_{2}$ bilayers with $3R$ crystal phase (AB stacking) show a significant valence-band splitting at the $K$ point estimated at $550\ifmmode\pm\else\textpm\fi{}20$ meV. We derived experimentally effective hole masses of $0.48{m}_{e}$ and $0.73{m}_{e}$ at the $K$ point for upper and lower bands, respectively. Our work opens up perspectives for the development of optoelectronic and spintronic devices based on $3R$ TMD homobilayers.