Ordered structure and high thermoelectric properties of Bi2(Te,Se)3 nanowire array

In this paper, novel Bi2(Te,Se)3 nanowire array structure can favorably influence the carrier and phonon transport properties. The ternary compound n-type Bi2(Te,Se)3 film, composed of ordered nanowire array, has been successfully fabricated by a simple thermal co-evaporation technique without using any templates. The measurement results show that the nanowire array is composed of single-crystalline Bi2(Te,Se)3 nanowires with diameter of about 20 nm. The well-oriented nanowires are parallel to each other and uniformly distributed. The growth mechanism of such nanostructure is proposed and investigated. The properties of the well-oriented Bi2(Te,Se)3 nanowire array have been greatly enhanced in comparison with those of the ordinary Bi2(Te,Se)3 film. The Bi2(Te,Se)3 nanowire array film with a thermoelectric dimensionless figure-of-merit ZT=1.01 was obtained at room temperature. Introduction of such ordered nanowire array architecture into films is therefore a very promising approach. Figure (a) Surface view and (b) cross-sectional view of the Bi2(Te,Se)3 nanowire array.