Flexible Thermoelectric Generator Based on Polycrystalline SiGe Thin Films

Tomoki Ozawa; Masayuki Murata; Takashi Suemasu; Kaoru Toko

doi:10.3390/ma15020608

Flexible Thermoelectric Generator Based on Polycrystalline SiGe Thin Films

Materials (Basel). 2022 Jan 14;15(2):608. doi: 10.3390/ma15020608.

Authors

Tomoki Ozawa¹, Masayuki Murata², Takashi Suemasu¹, Kaoru Toko¹

Affiliations

¹ Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8573, Japan.
² Research Institute for Energy Conservation, AIST, Tsukuba 305-8569, Japan.

Abstract

Flexible and reliable thermoelectric generators (TEGs) will be essential for future energy harvesting sensors. In this study, we synthesized p- and n-type SiGe layers on a high heat-resistant polyimide film using metal-induced layer exchange (LE) and demonstrated TEG operation. Despite the low process temperature (<500 °C), the polycrystalline SiGe layers showed high power factors of 560 µW m^-1 K^-2 for p-type Si_0.4Ge_0.6 and 390 µW m^-1 K^-2 for n-type Si_0.85Ge_0.15, owing to self-organized doping in LE. Furthermore, the power factors indicated stable behavior with changing measurement temperature, an advantage of SiGe as an inorganic material. An in-plane π-type TEG based on these SiGe layers showed an output power of 0.45 µW cm^-2 at near room temperature for a 30 K temperature gradient. This achievement will enable the development of environmentally friendly and highly reliable flexible TEGs for operating micro-energy devices in the future Internet of Things.

Keywords: flexible; layer exchange; low-temperature synthesis; polycrystalline SiGe; thermoelectric generator; thin film.

Abstract

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