Publications

Synthesis and Electrical Properties of a New Compound (BiSe)0.97(Bi2Se3)1.26(BiSe)0.97(MoSe2) Containing Metallic 1T-MoSe2

Choffel, Marisa A.; Gannon, Renae N.; Göhler, Fabian; Miller, Aaron M.; Medlin, Douglas L.; Seyller, Thomas; Johnson, David C.

The synthesis and electrical properties of a new misfit compound containing BiSe, Bi2Se3, and MoSe2 constituent layers are reported. The reaction pathway involves competition between the formation of (BiSe)1+x(Bi2Se3)1+y(BiSe)1+x(MoSe2) and [(Bi2Se3)1+y]2(MoSe2). Excess Bi and Se are required in the precursor to synthesize (BiSe)1+x(Bi2Se3)1+y(BiSe)1+x(MoSe2). High-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) confirm the stacking sequence of the heterostructure. Small grains of both 2H-and 1T-MoSe2 are observed in the MoSe2 layers. X-ray photoelectron spectroscopy (XPS) indicates that there is a significantly higher percentage of 1T-MoSe2 in (BiSe)1+x(Bi2Se3)1+y(BiSe)1+x(MoSe2) than in (BiSe)0.97(MoSe2), suggesting that more charge transfer to MoSe2 occurs due to the additional BiSe layer. The additional charge transfer results in (BiSe)1+x(Bi2Se3)1+y(BiSe)1+x(MoSe2) having a low resistivity (14-19 μω m) with metallic temperature dependence. The heterogeneous mix of MoSe2 polytypes observed in the XPS complicates the interpretation of the Hall data as two bands contribute to the electrical continuity.