Enhanced thermoelectric properties and their controllability in p-type (BiSb)2Te3 compounds through simultaneous adjustment of charge and thermal transports by Cu incorporation

We report the enhanced thermoelectric properties in CuxBi0.38Sb1.62Te3 compounds through simultaneous achievement of improved charge transport and suppressed thermal transport by Cu incorporation. Incorporated Cu acted as an acceptor rather than donor, resulting in the significant improvement of p-type electric conduction. Density of state effective mass was almost linearly proportional to the Cu content in the compounds, and it led to the enhancement of power factor in Cu-doped compounds regardless of the increase in hole concentration. Furthermore, reduction of bipolar and lattice thermal conductivities could also be achieved by the Cu incorporation, consequently leading to the improved thermoelectric properties of the compounds at relatively high temperatures. Effects of Cu on the thermal and charge transport properties are discussed in detail, and the controllability of the thermoelectric performance for optimum operating temperature is also reported.