Enhanced thermoelectric properties of Bi2Te3 doping Zn4Sb3 by combinatorial approach

Abstract

Materials derived from Bi2Te3 compounds are known to have advantageous thermoelectric properties at room temperatures, with the potential to be used in either cooling or power generating applications. In this paper, the effect of doping Bi2Te3 thin films with Zn4Sb3 is studied using a combinatorial approach. Findings from this study demonstrate the structural and thermoelectric properties of Bi2Te3/(Zn4Sb3)x thin films grown with varying Zn4Sb3 concentrations ranging from x=1at.% to 16.5at.%. The crystalline phase and variations in the composition of the thin films were determined using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). When doping Bi2Te3 with Zn4Sb3 concentrations of 5.1at.%, a dramatic change in electrical resistivity was observed. It was found that the electrical resistivity decreased from 6.68mΩ-cm to 1.63mΩ-cm when compared with undoped Bi2Te3, at room temperature. The power factor of Bi2Te3/(Zn4Sb3)x (x=5.1at.%) is 2.4μW/K2cm, which is higher than as-grown Bi2Te3 (1.4μW/K2cm), even though the Seebeck coefficient (−65.8μV/K) is slightly less than Bi2Te3 (−96.6μV/K). The observed effects on the thermoelectric properties of these materials are extremely important for understanding the fundamental characteristics of Zn4Sb3/Bi2Te3 embedded thermoelectric composites.