Verification of a Heat-electric Power Conversion Mechanism with Narrow Band Gap using the Thermal-probe Method

抄録

Thermoelectric power generation is based on the Seebeck effect and occurs with a temperature gradient. Recently, we prepared a single crystalline Ba₈Au_xSi_46-x clathrate with Au composition gradient and reported a heat-electric power conversion with narrow band gap. However, the mechanism was not clearly elucidated. In this study, we investigated carrier-generation behavior using the thermal-probe method during the heating. A single crystal of Ba₈Au_xSi_46-x clathrate was grown by the Czochralski method. Wavelength- dispersive X-ray spectroscopy showed that this single crystal has an Au-content gradient. The Seebeck coefficient of the sample was evaluated by the thermal probe method at room temperature and 300 °C. Results for 300 °C show that heating promotes a decrease of the Seebeck coefficient near the n/p interface. This decrease of the Seebeck coefficient indicated the electrons were excited by heating near the n/p interface.