HIGH-TEMPERATURE THERMOELECTRIC PERFORMANCE OF STRONTIUM TITANATE DEGENERATE SEMICONDUCTORS

摘要

Nb-content dependence of the thermoelectric figure of merit, ZT of SrTiO_3 at high-temperature (1000 K) is clarified using heavily Nb-doped SrTiO_3 epitaxial films, which were grown on (100)-face of LaAlO_3 single crystal substrates by a pulsed-laser deposition. Carrier concentration, Hall mobility, Seebeck coefficient, and thermal conductivity of Nb-doped SrTiO_3 epitaxial films were experimentally evaluated at 1000 K with an aid of theoretical analysis. ZT reached 0.37 (20%-Nb-doped SrTiO_3 epitaxial film) at 1000 K, which is the largest value among n-type oxide semiconductors ever reported.