Effect of Cu Deficiency on the Transport Behavior and Thermoelectric Properties in Cu3SbSe4

We investigate the effect of Cu deficiency on the transport behavior and thermoelectric properties in Cu3-delta SbSe4 in the temperature range of 300 - 650 K. Samples were synthesized by melt grown technique followed by spark plasma sintering. The electrical resistivity and thermal conductivity were found to decrease with increase in Cu deficiency till a certain limit (delta = 0.03), and after that, increase in electrical resistivity was observed. Positive value of Seebeck coefficient indicates p-type behavior of the carriers taking part in transport. Enhancement in power factor and thermoelectric figure of merit was achieved by controlling the transport of phonons and electrons, and a maximum thermoelectric figure of merit (0.59 at 650 K) was achieved for Cu2.98SbSe4 in this study.