High power factor in epitaxial Mg2Sn thin films via Ga doping

Abstract

In this work, we present the influence of Ga doping in Mg2Sn thin epitaxial films on sapphire (0001) substrates. Our results suggest that epitaxial nature is essential for achieving high mobility. Furthermore, we found that Ga incorporation influences the carrier concentration and acts as a phonon-scattering center. The optimal power factor and figure of merit values obtained were 1.49 × 10-3 W·m-1·K-1 and 0.08 at 300 K for Mg2Sn0.97Ga0.03. The values are in the same range as the bulk material of Mg-based II-IV semiconductors, suggesting that the combination of doping and epitaxial nature in thin films can be a promising route for miniaturization of thermoelectric devices based on Mg-based materials.