Thermal and Electronic Properties of Exfoliated Metal Chalcogenides

The thermal conductivity of layered metal chalcogenides such as <TEX>MT₂</TEX> (M = Mo, W; T = S, Se) shows a marked decrease after exfoliation and subsequent restacking process. Random stacking of two-dimensional crystalline sheets circumvents thermal conduction pathways along a longitudinal direction, which results in a reduction in thermal conductivity. <TEX>WS₂</TEX> and <TEX>WSe₂</TEX> compounds retain p-type conducting behavior after exfoliation and restacking with decreased electrical conductivity due to the change in carrier concentration. <TEX>MoSe₂</TEX> compound exhibits metallic behavior < <TEX>130∘C</TEX> with a small Seebeck coefficient, which results from metastable 1T-<TEX>MoSe₂</TEX> structure of the restacked phase.