Synthesis of a Family of ([SnSe]_1+δ)_m([{Mo_xNb_1x}Se₂]_1+γ)₁([SnSe]_1+δ)_m({Nb_xMo_1–x}Se₂)₁ Superlattice Heterostructures (m = 0, 1, 2, 3, 4 and 0.8 ≤ x ≤ 1)

Abstract

Abstract A family of multiple‐component heterostructures, ([SnSe] 1+ δ ) m ([{Mo x Nb 1– x }Se 2 ] 1+ γ ) 1 ([SnSe] 1+ δ ) m ({Nb x Mo 1– x }Se 2 ) 1 ( m = 0, 1, 2, 3, 4 and 0.8 ≤ x ≤ 1), was self‐assembled from designed amorphous precursors, and their structure and physical properties were characterized. The compounds consist of MoSe 2 and NbSe 2 layers with metal centers in a trigonal‐prismatic environment interleaved with systematically increasing numbers of SnSe bilayers with a distorted rock salt structure. The extent of alloying of the miscible dichalcogenide constituents decreased from about 20 % for m = 0 to less than 1 % for m = 3 and 4. The decreased alloying with increased SnSe thickness suggests the diffusion lengths of Mo and Nb during self‐assembly are about a nanometer. Resistivity and Hall coefficient measurements show that the electrical transport properties are similar to those of ([SnSe] 1+ δ ) m (NbSe 2 ) 1 ( m = 1–8) compounds, suggesting that the NbSe 2 layer dominates the conductivity and that charge transfer from SnSe reduces the carrier concentration in the NbSe 2 layer.