Extended Data Fig. 9: Moiré patterns of SnS2/WSe2 roll-up vdW superlattice.
From: High-order superlattices by rolling up van der Waals heterostructures
a, Low-resolution TEM image of a SnS2/WSe2 roll-up. Scale bar, 1 μm. b, SAED image of the SnS2/WSe2 roll-up. Scale bar, 5 nm−1. The white dashed double arrow indicates the axis direction of the roll-up, and the two red dashed lines indicate the major axis of the top wall and bottom wall, which forms a chiral angle of θ = ±22° with the roll-up axis. c, High-angle annular dark-field STEM image of the periodic moiré superlattices of the SnS2/WSe2 vdW superlattice roll-up; the yellow dashed rhombus is the corresponding moiré unit cells with moiré superlattice constant LM = 3.34 nm. Scale bar, 2 nm. The moiré superlattice results from the SnS2/WSe2 heterobilayer on the top wall of the roll-up. The red dashed line indicates a major axis of the top-wall SnS2/WSe2 heterobilayer and has a chiral angle of θ = 22° from the roll-up axis (white dashed double arrow). d, The corresponding atomic model of the heterobilayer moiré superlattices of SnS2/WSe2. Scale bar, 2 nm. Lattice constants of 0.33 nm and 0.37 nm were used for WSe2 and SnS2, respectively. e, TEM image of the periodic moiré superlattices of the SnS2/WSe2 roll-up. The blue dashed rhombus is the corresponding moiré unit cell with LM = 2.29 nm. Scale bar, 2 nm. The moiré superlattice mainly results from WSe2 in the top wall and the WSe2 bottom wall, with a folding (twist) angle of 44° between the top and bottom WSe2. The two red dashed lines indicate the major axes of the top and bottom walls, which form a chiral angle of ±22° with the roll-up axis (white dashed double arrow). f, The corresponding atomic model of the moiré superlattices of WSe2/WSe2 homostructure with a folding angle of 44°. Scale bar, 2 nm.
