Strain driven anomalous anisotropic enhancement in the thermoelectric performance of monolayer MoS2

Hydrostatic Pressure-Induced Anomalous Enhancement in the Thermoelectric Performance of Monolayer MoS2

“…The excellent combination of electrical and thermal transport in these 2D materials leads to a significantly large thermoelectric zT . , Over the years, various 2D materials, viz., transition metal dichalcogenides (TMDCs) (e.g., MoS 2 , WS 2 , MoSe 2 , and HfS 2 ) and group IVA-VA compounds (e.g., SnSe, SnS, and GeSe), have emerged as potential TEM with reasonably good thermoelectric performance. − In recent times, especially the layered TMDCs have drawn significant interest owing to their tunable band gap, high electrical mobility, and low thermal conductivity. − Some of the TMDCs, such as WS 2 , WSe 2 , HfS 2 , and SnSe 2 , have shown notably high thermoelectric efficiency. Among the family of TMDCs, MoS 2 has been explored extensively as a potential TEM, both theoretically ,− and experimentally, , and the monolayer (ML) counterpart appears to be a reasonably good TEM. ,,,, Hippalgaonkar et al have measured the room-temperature thermoelectric power factor of ML-MoS 2 to be 8.5 mW K –2 m –1 , which is comparable to the well-known TEMs, such as Bi 2 Te 3 . Buscema et al have found a large Seebeck coefficient in ML-MoS 2 , which is also tunable by an external electric field.…”

“…The upper limit of the temperature is well within the thermal stability regime of ML-MoS 2 , which was analyzed using molecular dynamics (MD) calculations in our earlier work. 31 The S and PF are plotted as a function of temperature for different hydrostatic pressures under electron and hole doping (see Figure 3b,d). For the electron doping, both these quantities are found to be the highest at a pressure of 10 GPa for the entire temperature range due to the increased degeneracy at the CBM.…”

“…Efforts have been made to improve the thermoelectric efficiency of ML-MoS 2 by applying an external electric field or mechanical strain. ,,,,, Doping with impurity atoms and hybridization are the widely explored avenues in improving the zT of a material. ,, In-plane strain engineering has also been employed routinely to tune the electronic and thermoelectric properties of various 2D materials, such as WS 2 , ZrS 2 , HfS 2 , and ZnO. ,,, In one of our earlier studies, we have seen that the in-plane tensile strains, in general, and the strains along the zigzag direction, in particular, can significantly enhance the thermoelectric efficiency of ML-MoS 2 . However, the implementation of different in-plane strains in experiments is a daunting task. − Application of hydrostatic pressure, on the other hand, can be a potential easier alternative route that can be achieved experimentally owing to the fairly simple procedure and reversibility.…”

“…Efforts have been made to improve the thermoelectric efficiency of ML-MoS 2 by applying an external electric field 34 or mechanical strain. 11, 23,25,28,30,31 Doping with impurity atoms and hybridization are the widely explored avenues in improving the zT of a material. 9,38,39 In-plane strain engineering has also been employed routinely to tune the electronic and thermoelectric properties of various 2D materials, such as WS 2 , ZrS 2 , HfS 2 , and ZnO.…”

“…12,23,40,41 In one of our earlier studies, we have seen that the in-plane tensile strains, in general, and the strains along the zigzag direction, in particular, can significantly enhance the thermoelectric efficiency of ML-MoS 2 . 31 However, the implementation of different in-plane strains in experiments is a daunting task. 42−46 Application of hydrostatic pressure, on the other hand, can be a potential easier alternative route that can be achieved experimentally owing to the fairly simple procedure and reversibility.…”