Impurity states in Mo1−xMxSe2 compounds doped with group VB elements and their electronic and thermal transport properties

摘要: The impurity states introduced by substitutional doping of Mo1−xMxSe2 with group VB (M = V, Nb and Ta), their effect on the thermoelectric properties were systematically investigated via DFT calculations experiments. We find that lightly doped (x 0.01) exhibits a hopping conduction at low temperatures owing to discrete near valence band maximum (VBM) host. Increasing level gives rise an VBM Mo1−xMxSe2, leading metallic characteristics. And, increase carrier effective mass due coincidence in energy topmost bands Γ K. Moreover, substitution Mo M dramatically reduces lattice thermal conductivity (κL) Mo1−xMxSe2. As result significantly improved electronic reduced κL, M-doped samples exhibit remarkable enhancements figure merit ZT. Ta-doped Mo0.95Ta0.05Se2 0.05) sample possesses ZTmax 0.12 0.14 measured perpendicular parallel pressing direction, respectively. This work provides some insights towards understanding MoSe2 other transition metal dichalcogenides (TMDs).