Improved p-and n-type thin-film microstructures for thermoelectricity

Abstract

Improved microstructures based on thin-films of n-type bismuth telluride (Bi2Te3) and p-type antimony telluride (Sb2Te3) to convert temperature differences in electricity are presented. The microstructures are obtained by thin-film deposition, applying the co-evaporation method to the bismuth/antimony and telluride materials. Measurements demonstrated the superior thermoelectric features of the obtained films when compared with the most recent thermoelectric thin-film deposition. Measurements show that the deposited films present thermoelectric properties comparable to those reported for the same materials in bulk form, as is the case of the materials used in conventional macro-scale Peltier modules. The absolute values of the Seebeck coefficient are in the range 150–250 mVK21 and the in-plane electrical resistivity is in the 7–15 mVm range. Measurements for the Bi2Te3 and Sb2Te3 films also show figures of merit at room temperatures of 0.84 and 0.5, and power factors of 4.87 and 2.81 mWK22 m21, respectively. These microstructures are used for the fabrication of thermoelectric microgenerators to supply stand-alone microsystems with power consumption that ranges from cents of mW to a few mW.