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DS: Fachverband Dünne Schichten
DS 15: Thermoelectric and Phase Change Materials
DS 15.5: Talk
Thursday, March 21, 2024, 11:30–11:45, A 060
Field Effect Control of Thermoelectric Effect in Semiconductor Thin Films — •Sunao Shimizu1, Kazumoto Miwa2, Kazuyasu Tokiwa3, and Shimpei Ono1 — 1Toyama Prefectural University, Toyama, Japan — 2CRIEPI, Kanagawa, Japan — 3Tokyo University of Science, Tokyo, Japan
Thermoelectric energy conversion has recently regained an increased interest as a promising technology for renewable energy systems. It is highly required to investigate diverse semiconductors for developing thermoelectric modules with higher energy conversion efficiency. In this presentation, we report the systematic characterization of thermoelectric properties in WO3. We fabricated WO3 thin films by RF sputtering and applied an ionic liquid gating technique to precisely control the carrier density. Due to the high gate capacitance at the electric double layer [1], which is formed at the interface of WO3 and the ionic liquid, high density charge carriers were accumulated on the semiconductor surface by just applying several volts of the gate voltage. The temperature dependence of the sheet resistance in WO3 initially showed insulating behavior and was modified to be metallic by the ionic liquid gating. We also discuss the systematic change of the thermoelectric effect, showing the optimization of the thermoelectric power factor with changing the carrier density [2].
[1] S. Bisri, S. Shimizu, M. Nakano, Y. Iwasa, Adv. Mater. 29, 1607054 (2017). [2] S. Shimizu et al., Sci. Rep. 12, 7292 (2022).
Keywords: thin film; oxide semiconductor; field effect transistor; thermoelectric; carrier doping