Investigation of Thermoelectric Semiconductors with Electric Double Layer Gating
Thermoelectric energy conversion has recently regained an increased interest as a promising technology for generation of renewable energy. It is highly required to develop novel thermoelectric materials from diverse library of functional materials. For exploring thermoelectric semiconductors, we have applied an ionic liquid gating technique as a tool to systematically control the carrier density. Due to the high gate capacitance at the electric double layer, high density charge carriers are accumulated on the semiconductor surface by just applying several volts of the gate voltage. The highest carrier density reaches up to 10 14 ~ 10 15 cm -2 , which covers insulating to metallic region of inorganic materials.
In this presentation, we would like to report our recent studies on thermoelectric materials investigated by electric double layer transistor (EDLT) configurations. We will present how the thermoelectric effect is modulated by liquid gating and would like to discuss their properties unique to their intrinsic band structures. Our approach is applicable to wide range of materials, opening up a novel route to realize thermoelectric devices with advanced functionalities.