Carrier scattering mechanism change in Se and S co-doped AgSbTe2 thermoelectric materials

Abstract

The Single Parabolic Band (SPB) model is a valuable tool for calculating electronic band parameters and predicting thermoelectric performance of materials from single-sample experimental data. However, accurate selection of the dominant carrier scattering mechanism is crucial for reliable band parameter estimation. This study investigates the influence of scattering mechanisms on predicted band parameters for Se and S co-doped AgSbTe2, building upon recent findings by Zhang et al. We employ the SPB model with two carrier scattering scenarios: acoustic phonon scattering and mixed scattering (acoustic phonon + ionized impurities). This allows us to examine how assumptions regarding carrier scattering mechanisms affect various band parameters, including density-of-states effective mass, nondegenerate mobility, weighted mobility, and thermoelectric quality factor. Our results reveal significant discrepancies in the predicted band parameters depending on the assumed scattering mechanism. Notably, the predicted power factor of Se and S co-doped AgSbTe2 varies from similar to 2.5 to 2.9 mW/mK(2), along with the optimal carrier concentration. This study not only improves our understanding of the thermoelectric behavior of Se and S co-doped AgSbTe2 but also demonstrates the potential of employing the SPB model with different scattering mechanisms for materials where the dominant scattering mechanism changes with doping.