Large thermoelectric figure of merit at high temperature in Czochralski-grown clathrate Ba8Ga16Ge30

Artikel i vetenskaplig tidskrift, 2006

The Czochralski method was used to grow a 46-mm -long crystal of the Ba8 Ga16 Ge30 clathrate, which was cut into disks that were evaluated for thermoelectric performance. The Seebeck coefficient and electrical and thermal conductivities all showed evidence of a transition from extrinsic to intrinsic behavior in the range of 600-900 K. The corresponding figure of merit (ZT) was found to be a record high of 1.35 at 900 K and with an extrapolated maximum of 1.63 at 1100 K. This makes the Ba8 Ga16 Ge30 clathrate an exceptionally strong candidate for medium and high-temperature thermoelectric applications.