Reactive spark plasma sintering and thermoelectric properties of Nd-substituted BiCuSeO oxyselenides

Abstract Bi 1- x Nd x CuSeO ( x  = 0; 0.05; 0.10; 0.15) was fabricated by the solid-state reaction and the reactive spark plasma sintering for comparative study. It was demonstrated that BiCuSeO could be formed in-situ by the reaction between Bi 2 O 3 , Bi, Cu and Se during the densification process. The effect of Nd doping on the thermoelectric properties has been investigated. The results indicated that for both series of the samples the substitution of Bi 3+ by Nd 3+ resulted in the increase of charge carrier concentration mainly caused by Bi/Cu deficiencies formation with the substitution. However, the specimens obtained by reactive spark plasma sintering had lower hole concentration which may originate from the high speed of the process resulted in induced point defect and interface scattering and another phase formation mechanism leading to the smaller amount of Bi/Cu deficiencies.