Thermoelectric properties of α-Zn3P2

The potential of the semiconducting compound α-Zn₃P₂ for thermoelectric application was investigated. α-Zn₃P₂ has a tetragonal crystal structure with a relatively complex unit cell, which results in a low lattice thermal conductivity. Several samples of α-Zn₃ P₂ 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 α-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 μVK^-1 were obtained on the p-type 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 mW cm^-1K^-1. The optimization of the electronic properties will be required to achieve the high thermoelectric figure of merit