Thermoelectric Enhancement in Lateral Transition-Metal Dichalcogenide Heterostructures

Increasing demands for renewable sources of energy has been a major driving force for developing efficient thermoelectric materials. Two-dimensional (2D) transition-metal dichalcogenides (TMDC) have emerged as promising candidates for thermoelectricity due to their large effective masses and low thermal conductivity. Here, we study the thermoelectric performance of lateral TMDC heterostructures within a multiscale quantum transport framework. Both n-type and p-type lateral heterostructures are considered for all possible combinations of semiconducting TMDCs: MoS2, MoSe2, WS2, and WSe2. The band alignment between the materials is found to play a crucial in enhancing the thermoelectric figure-of-merit (ZT) and power factor far beyond the pristine TMDCs. In particular, we show that the room-temperature ZT value of n-type WS2 with WSe2 triangular inclusions is five times larger than the pristine WS₂ monolayer. p-type MoSe2 with WSe2 inclusions is also shown to have a room-temperature ZT value about two times larger than the pristine MoSe2 monolayer. The peak power factor values calculated here, are the highest amongst the gapped 2D monolayers at room temperature. Hence, 2D lateral TMDC heterostructures opens new avenues to construct ultra-efficient in-plane thermoelectric devices.