Fig. 2: Mechanism of remote epitaxy of R-stacked bilayer WS2 single crystals on a-plane sapphire.
From: Remote epitaxy of single-crystal rhombohedral WS2 bilayers
a Schematic diagrams of the step-guided epitaxy of bilayer WS2 on high steps. Each layer of TMD bonds to the side of the steps. b Schematic diagrams of the remote epitaxy of bilayer WS2 on atomic steps. The in-plane direction and interlayer stacking of bilayer WS2 can both be tuned by the steps. c Formation energies of R- and H-stacked bilayer WS2 with different rotation angles on a-plane sapphire without steps. Bilayer TMD has the same deep minima as monolayer (θ = 0° and θ = ±60°). d Binding energies of R- and H-stacked bilayer WS2 that across an atomic step on a-plane sapphire.
