Achieving high power factor in GaSb with intrinsically high mobility via Ge doping

The thermoelectric power factor is as crucial as their overall thermoelectric performance. GaSb-based compounds are deemed to achieve high power factor owing to their intrinsically high mobility compared to classical thermoelectric materials. However, the carrier concentration of pristine GaSb is considerably lower than the optimum value, which hinders its ability to attain high electrical performance. In this paper, we present the investigations on the thermoelectric performance of p-type GaSb_1−xGe_x samples. The experimental results reveal that Ge doping can effectively tune the carrier concentration. Consequently, both the peak and average power factors show significant enhancement. In the sample with x = 0.03, the average power factor increased from 0.35 to 1.95 mW·m⁻¹·K⁻² in relation to that of pristine GaSb. Additionally, a peak thermoelectric figure of merit (zT) value of 0.27 was obtained at 800 K for the GaSb_0.97Ge_0.03 sample. This study demonstrates that Ge doping is an effective method for optimizing carrier concentration and enhancing the electrical performance of GaSb-based compounds.