Enhanced thermoelectric properties of Cu doped ZnSb based thin films

Cu doped ZnSb based thin films were deposited by direct current magnetron co-sputtering. X-ray diffraction results show that the un-doped thin film reveals a single ZnSb phase and it transforms to Zn4Sb3 phase after Cu doped. The material with Zn4Sb3 phase which belongs to R-3c space group crystal will lead to lower thermal conductivity. The Hall effect measurement shows that the samples are P-type semiconductors. The electrical conductivity increasers after Cu doped due to the increase of carrier concentration and the improvement in crystallinity. Though the Seebeck coefficient decreases after Cu doped, the ZT value increases from 0.11 to 0.43 with higher electrical conductivity and lower thermal conductivity at room-temperature. The temperature-dependent of ZT value is estimated to be similar to 1.35 for the thin film with Zn4Sb3 phase by using the bulk lattice thermal conductivity together with the thin film electrical thermal conductivity. (C) 2016 Elsevier B.V. All rights reserved.