Synthesis and Characterization of Quaternary Monolayer Thick MoSe2/SnSe/NbSe2/SnSe Heterojunction Superlattices

• Published in: Chemistry of materials Vol. 27; no. 18; pp. 6411 - 6417
• Main Authors: Westover, Richard D, Ditto, Jeffrey, Falmbigl, Matthias, Hay, Zachary L, Johnson, David C
• Format: Journal Article
• Language: English
• Published: American Chemical Society 22.09.2015
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.5b02588

The synthesis of multiple-component heterostructures is conventionally accomplished through mechanical or chemical exfoliation, followed by physically stacking the layers together. Here, we report the synthesis, structure, and local composition of a three-component heterostructure (SnSe)1.16(MoSe2)1.06­(SnSe)1.16­(NbSe2)1, which was self-assembled at relatively low temperature (450 °C) from a designed precursor. XRD and STEM studies showed that the compound consisted of alternating layers of trigonal prismatic MoSe2 and NbSe2, interleaved with SnSe layers in a distorted rock salt structure. The new three-component ferecrystal is metallic with a factor of 3 higher conductivity than the (SnSe)1+δ­(Nb x Mo1–x )­Se2 ferecrystal alloy of the same composition (x ≈ 0.5). Comparison of the in-plane lattice parameters with the (SnSe)1+δ(Nb x Mo1−x )­Se2 alloys allowed the extent of interdiffusion of the dichalcogenide constituents to be evaluated, yielding a stoichiometry of (SnSe)1.16­([Mo0.9Nb0.1]­Se2)1.06­(SnSe)1.16­([Nb0.9Mo0.1]­Se2)1.