Thermoelectric Properties of In_4Se_3 Synthesized by Combing Sonochemical and SPS Method

Single-phase In4Se3 powders were synthesized by a sonochemical method combined with subsequent deoxidizing heat-treatment,and a bulk sample was prepared via a spark plasma sintering(SPS) method.The phase composition,microstructures and thermoelectric transport properties of the as-prepared bulk sample were studied.The bulk sample possesses refined crystalline and obvious anisotropy observed in the different directions,where a large number of fine layered structures exist along the SPS pressing direction.Therefore,the thermoelectric properties of the bulk sample also show significant anisotropy.Owing to higher Seebeck coefficient and lower thermal conductivity,a better ZT is achieved in direction of the SPS pressure compared with the perpendicular direction.As a result,the maximum ZT reaches 0.56 at 700 K,which is comparable with that of the samples synthesized by other physical techniques.