Thermoelectric properties of α-Zn/sub 3/P/sub 2/

Abstract

The potential of the semiconducting compound /spl alpha/-Zn/sub 3/P/sub 2/ for thermoelectric application was investigated. /spl alpha/-Zn/sub 3/P/sub 2/ has a tetragonal crystal structure with a relatively complex unit cell, which results in a low lattice thermal conductivity. Several samples of /spl alpha/-Zn/sub 3/P/sub 2/ 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 /spl alpha/-Zn/sub 3/P/sub 2/ 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 /spl mu/VK/sup -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/sup -1/K/sup -1/. The optimization of the electronic properties will be required to achieve the high thermoelectric figure of merit.