Abstract
Thermoelectric figure of merit of AgBiTe2 -Ag2Te composites is increased by scattering efficiently long-wavelength phonons1, 2 at the boundaries between AgBiTe2 and Ag2Te. We prepared AgBiTe2 alloys dispersed with Ag2Te grains of (AgBiTe2)1-x(Ag2Te)x(0<x<1). Electrical conductivity, Seebeck coefficient, and thermal conductivity of AgBiTe2-Ag2Te composites depended on contents, sizes and textures of Ag2Te grains. Comparing the experimental values with the calculated values based on conductivity equation3, 4, 5, 6 with no phonon and electron scattering at the boundaries, we have found that the thermoelectric figure of merit has the maximum when the Ag2Te grain size is around 10μm, when the phonon scattering is larger than electron scattering.
