Synthesis of a Family of ([SnSe]1+δ)m­([{MoxNb1x}Se2]1+γ)1([SnSe]1+δ)m­({Nbx­Mo1–x}Se2)1 Superlattice ­Heterostructures (m = 0, 1, 2, 3, 4 ­and 0.8 ≤ x ≤ 1)

Abstract

AbstractA family of multiple‐component heterostructures, ([SnSe]1+δ)m([{MoxNb1–x}Se2]1+γ)1([SnSe]1+δ)m({NbxMo1–x}Se2)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 MoSe2 and NbSe2 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(NbSe2)1 (m = 1–8) compounds, suggesting that the NbSe2 layer dominates the conductivity and that charge transfer from SnSe reduces the carrier concentration in the NbSe2 layer.