Thermoelectric Effect in Janus Monolayer InSSe

Thermoelectric effect in Janus monolayer InSSe is investigated by non-equilibrium Green's function and density functional theory. Janus monolayer InSSe is an indirect gap semiconductor with a bandgap of 1.24 eV. The value of the thermoelectric figure of merit is up to 4.39 at the temperature of 500 K and 1.38 at room temperature. We found a remarkably low and anisotropic phononic thermal conductance about 0.05987 WK –1 m –1 , which is originated from the soft lattice vibration modes. This low thermal conductance is responsible for the high value of the figure of merit. All the results indicate that Janus monolayer InSSe is a more suitable low dimensional thermoelectric material.