Optimum operating-temperature range and lifetime estimate for ZnSb:0.1 at % Cu thermoelectrics

The temperature dependences of concentration and mobility are investigated in 300–700–300 K thermal cycles at different durations of low-temperature annealing of a ZnSb:0.1 at % Cu sample before the onset of every thermal cycle. Concurrently, the material is annealed for 1500 hours at a temperature difference of 310–670 K, and, then, its thermoelectric parameters are measured. The results are analyzed taking into account the features of the crystalline structure and the covalent nature of the chemical bonds in ZnSb. The operating range and lifetime of this composition are estimated on the basis of a model of the interaction of impurity defects with a decrease in their acceptor activity and an increase in the hole-scattering cross section at low temperatures.