Band Engineering and Thermoelectric Performance Optimization of p-Type GeTe-Based Alloys through Ti/Sb Co-Doping

GeTe-based materials usually possess brilliant thermoelectric performance through band degeneracy and optimized carrier concentration. In this study, Ti doping is effective for the realization of band degeneracy. However, the high carrier concentration after Ti doping limited the enhanced thermoelectric performance. Accordingly, Sb was used to optimize hole carrier concentration. Combined with the decreased thermal conductivity, the enhanced power factors, due to band degeneracy and carrier concentration optimization, result in a high zT of 1.60 in Ge 0.92 Ti 0.01 Sb 0.07 Te. The achieved high zT demonstrates that the p -type Ti/Sb co-doped GeTe compounds are promising as mid-temperature thermoelectric materials.