Power Factor Characterization of Ge/SiGe Thermoelectric Superlattices at 300 K
To accurately characterize the efficiency of thermoelectric materials and characterize the maximum power that they can produce, a device using micro/nanofabrication techniques has been developed, enabling all three properties included in the figure of merit, ZT, of a thermoelectric material to be measured using a single device. The fabrication and testing of the device are presented. The electrical conductivity and Seebeck coefficient of Ge/SiGe heterostructures grown by low-energy plasma-enhanced chemical vapor deposition are used for demonstration. Experimental results as a function of quantum well width are presented, demonstrating power factors up to 6.02 ± 0.05 mW m−1 K−2 at 300 K. Modeling and physical characterization demonstrate that these results are presently limited by high threading dislocation density.