Enhanced Thermoelectric Properties of Suspended Mono- and Bilayer of MoS 2 From First Principles

The past decade has seen the emergence of two-dimensional MoS 2 as a very promising material for numerous applications in nanoelectronics and photonics and investigation of its thermoelectric properties is highly significant. The thermoelectric performance of suspended monolayer (ML) and bilayer (BL) of MoS 2 has been investigated using density functional theory simulations and the semiclassical Boltzmann's theory. Using the BotzTrap code within the constant relaxation time approximation, we report in plane (armchair direction) figures of merit ( ZT ) values close to one and Seebeck coefficients ( S ) greater than 2000 μV/K for these layers at the optimal doping concentration of ∼10 21 cm –3 . The general trend for both the layers with temperature is a decrease in S and increase in thermal conductivities $(\kappa/\tau)$ . ZT values on the other hand show a decrease in the ML and an increase in the BL with values of 0.97 and 0.87 for the ML and 0.98 and 1.04 for the BL at temperatures of 300 and 1000 K, respectively, for the n-type. These very attractive ZT values for the suspended ML and BL as compared to the bulk value of 0.18 at 300 K hold great promise for low-dimensional MoS 2 as an efficient thermoelectric performer.