Thermoelectric Properties of a-ZnsPz

The potential of the semiconducting compound a-Zn3P2 for thermoelectric application was investigated. a-Zn3P2 has a tetragonal crystal structure with a relatively complex unit cell, which results in a low lattice thermal conductivity. Several samples of a-Zn3P2 were prepared using the solid-state reacted powders by the spark plasma sintering method. The electrical conductivity and the Seebeck coefficient measurements were performed over the temperature range 300-1000 K. The electrical conductivity of undoped w-Zn3P2 was found to be considerably lower than that of state-of-the-art thermoelectric materials. The electrical conductivity was increased by the substitution of Cu for Zn. Large Seebeck coefficients up to about 900 14VK-l were obtained on the ptype undoped sample. The thermal conductivity was measured by the laser flash method over the temperature range 300-800 K. The obtained samples had relatively low thermal conductivity values and the room-temperature lattice thermal conductivity was estimated to be 13 mWcm-lK-'. The optimization of the electronic properties will be required to achieve the high thermoelectric figure of merit.