In both the rhombohedral and the cubic phase GeTe, resonant levels induced by indium dopants have been demonstrated. The experimental Seebeck coefficients of InxGe1−xTe show large enhancement as compared with other prior dopants. The enhanced Seebeck coefficient, combined with the reduced thermal conductivity, leads to a reasonably high ZT of 1.3 near 355 °C in In0.02Ge0.98Te. The average ZT is enhanced by ~70% across the whole temperature range. The present results suggest that indium-doped GeTe can be a promising base-material for even higher thermoelectric performance.
