MoS2 nano flakes with self-adaptive contacts for efficient thermoelectric energy harvesting

Abstract

We examine the potential of the low-dimensional material MoS₂ for the efficient conversion of waste heat to electricity via the Seebeck effect. Recently monolayer MoS₂ nano flakes with self-adaptive Mo₆S₆ contacts were formed, which take advantage of mechanical stability and chemical covalent bonding to the MoS₂. Here, we study the thermoelectric properties of these junctions by calculating their conductance, thermopower and thermal conductance due to both electrons and phonons. We show that thermoelectric figures of merit ZT as high as ∼2.8 are accessible in these junctions, independent of the flake size and shape, provided the Fermi energy is close to a band edge. We show that Nb dopants as substituents for Mo atoms can be used to tune the Fermi energy, and despite the associated inhomogeneous broadening, room temperature values as high as ZT ∼ 0.6 are accessible, increasing to 0.8 at 500 K.