Electric field modulation of thermovoltage in single-layer MoS2

We study electric field modulation of the thermovoltage in single-layer MoS2. The Seebeck coefficient generally increases for a diminishing free carrier concentration, and in the case of single-layer MoS2 reaches considerable large values of about S = -5160 mu V/K at a resistivity of 490 Omega m. Further, we observe time dependent degradation of the conductivity in single layer MoS2, resulting in variations of the Seebeck coefficient. The degradation is attributable to adsorbates from ambient air, acting as p-dopants and additional Coulomb potentials, resulting in carrier scattering increase, and thus decrease of the electron mobility. The corresponding power factors remain at moderate levels, due to the low conductivity of single layer MoS2. However, as single-layer MoS2 has a short intrinsic phonon mean free path, resulting in low thermal conductivity, MoS2 holds great promise as high-performance 2D thermoelectric material. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.