Thermoelectric properties of two-dimensional MoS₂ semiconductors in a wide temperature range

Although the hopping transport in thermoelectric (TE) power and conductance of single-layer MoS₂ was experimentally studied, the relation between the disorder parameter and the TE power was not investigated yet. Nor did the conduction mechanism at temperatures above 450 K be studied regarding to the TE power. Further, the TE power factor was essential for the applications while its temperature, layer thickness, and carrier concentration dependences were not completely explored yet. Here we will report the fabrication of both TE and field-effect transistor devices based on MoS₂ flakes with a thickness from single layer to 39 layers. In particular, the TE properties of the two-dimensional MoS₂ semiconductor are studied in a wide temperature range from 80 to 600 K. We will talk about the intrinsic disorder effects on the TE power and electron transport at temperature below 200 K. At temperatures ranging from 300 to 450 K, we will investigate thermal activation and discuss its effects on the TE power. In addition, at temperatures above 450 K, we will show an extrinsic effect which comes from the interface between the MoS₂ flake and the SiO₂ dielectric layer. The extrinsic effect leads to a memory effect while it offers an enhancement of TE power factor at high temperatures.