Structure and Property Characterization of Bi_(2-x)Sb_xTe_3 Thermoelectric Films Prepared by Electrodeposition

Bi2-xSbxTe3 thermoelectric films were prepared by potentiostatic electrodeposition. The morphology, structure and composition of the electrodeposited films were investigated by ESEM, XPS, XRD, and EDS. And the Seebeck coefficients of Bi2-xSbxTe3 thermoelectric films electrodeposited at different potentials were measured. The results indicate that bismuth, antimony and tellurium can be coelectrodeposited to form Sb doped Bi2Te3 compouds Bi2-xSbxTe3 in the solution containing Bi3+, HTeO2+ and SbO+. The doping concentration of Bi2-xSbxTe3 thermoelectric films can be controlled through adjusting electrodeposition potential to affect their thermoelectric properties. The composition of the film electrodeposited at -0.5V is Bi0.5Sb1.5Te3, and it has the largest Seebeck coefficient of 213μV·K-1. With the decrease of electrodeposition potential, the crystalline state of Bi2-xSbxTe3 film will transform from equiaxed crystal into dendritic crystal. The study shows that the electrodeposition process can be successfully used to synthesize the thermoelectric films with better properties.