2:00 PM - 2:15 PM
[13p-1A-3] Thermoelectric properties of transition metal dichalcogenide monolayers
Keywords:transition metal dichalcogenide,thermoelectric property
Monolayer transition metal dichalcogenides (TMDCs) have attracted a lot of research interests due to their two-dimensional layer structure. Recently, in single-crystal monolayer MoS2, extremely high Seebeck coefficient (> 100 mV/K) was reported, suggesting high thermoelectric efficiency due to the low dimensional system. As a next step, it is necessary to investigate thermoelectric properties of other TMDC monolayers to search better thermoelectric materials. Particularly, for future applications, the large-area polycrystalline samples should be tested. Moreover, because Seebeck coefficient correlates with carrier density strongly, we should control the carrier density of samples to maximize Seebeck coefficient. Therefore, in this research, we clarify the carrier density dependence of Seebeck effect in CVD-grown large-area WSe2, WS2 and MoS2 monolayers. For carrier-density control, we fabricated electric double layer transistors (EDLTs) using ion gel, which is the mixture of ionic liquid and organic polymer. Finally, we successfully accumulated hole and/or electron carriers (> 1013 cm-2) and obtained relatively high Seebeck coefficient (~100 mV/K) for all in monolayer TMDC films.