Thermoelectric Module of SiGe Bulk Alloys Forming p‐n Junction at the Hot Side
Shinichi Fujimoto, Kazuo Nagase, Hironori Ohshima, Masayuki Murata, Atsushi Yamamoto, Chul‐Ho Lee
Abstract
Thermoelectric power generation is a potential technology for providing green energy. It is expected to be able to convert enormous amounts of waste heat to electrical energy. To realize this technology, further increases in conversion efficiency and durability are essential. In particular, durability is a critical issue, especially for harnessing high‐temperature heat sources. Thus, a thermoelectric module of SiGe is fabricated without electrodes at the hot side, which is the main cause of aging. Electronic conduction between p ‐ and n‐type elements is alternatively introduced using a direct connection, forming a p ‐n junction. Sufficiently low electrical contact resistances are achieved at the p ‐n junction above 300 °C due to the dissipation of the depletion layer. The conversion efficiency is 2.0% with a hot‐side temperature of 700 °C. The power‐generation performance is constant during heat‐run tests conducted at 700 and 500 °C under vacuum and air, respectively, for more than 450 h. The results demonstrate that a stable power‐generation technology using a thermoelectric module at high temperatures is established successfully.