Multilayered structure and enhanced thermoelectric properties of Bi_1.5 Sb_0.5 Te₃ film with preferential growth

Abstract

In this paper, uniquely (0 1 5)-preferential growth plane and alternating stress field can favorably influence the carrier and phonon transport properties of multilayered films. The p-type Bi 1.5 Sb 0.5 Te 3 multilayered film has been successfully fabricated by a simple thermal co-evaporation technique. The composition, microstructure, and in-plane thermoelectric (TE) properties of films have been characterized and measured, respectively. The measurement results show that the multilayered Bi 1.5 Sb 0.5 Te 3 film is (0 1 5)-preferential growth. The multilayered structure film is composed of the (0 1 5)-oriented and the ordinary nanolayers. The properties of the multilayered Bi 1.5 Sb 0.5 Te 3 film has been significantly enhanced in comparison with those of the highly (0 1 5)-oriented and the ordinary Bi 1.5 Sb 0.5 Te 3 films. The multilayered Bi 1.5 Sb 0.5 Te 3 film with a TE dimensionless figure-of-merit ZT ¼ 1.28 was obtained at room temperature. The transport mechanism of multilayered structure is proposed and investigated. The internal strain field and (0 1 5)-preferential growth plane are the main reasons for the properties enhancement observed in the multilayered Bi 1.5 Sb 0.5 Te 3 film. Introduction of such uniquely (0 1 5)-preferential growth plane and alternating stress field into TE films is therefore a very promising approach.

Effects of working pressure during magnetron sputtering on thermoelectric performance of flexible p-type Bi0.5Sb1.5Te3 thin films

“…36 For the BST2a film, the S max ∼ 188 μV/K appears at 355 K. For the BST4a and BST5a films, the S max is slightly increased to ∼191 μV/K at 380 K. This value is relatively high and comparable with those reported previously for Bi 0.5 Sb 1.5 Te 3 films, which could be attributed to the quantum confinement effect. 37,38 Moreover, in the whole testing temperature range, their S values are superior to that of the BST2a film. Generally, the Seebeck coefficient S can be expressed as…”

An overview of thermoelectric films: Fabrication techniques, classification, and regulation methods

“…3. [63] Zhu et al [67] achieved the preferential growth transformation from (015) plane to (00l) plane of Bi 0.5 Sb 1.5 Te 3 film by a facile post-annealing process, as illustrated in Fig. 4, and TE performance was enhanced.…”

“…The p-type (015)-preferential Bi 1.5 Sb 0.5 Te 3 multilayered film was deposited by a simple thermal co-evaporation technique, having a room-temperature zT of 1.28. And the in-plane transport mechanism was shown in Fig.3 [63]. Zhu et al[67] achieved the preferential growth transformation from (015) plane to (00l) plane of Bi 0.5 Sb 1.5 Te 3 film by a facile post-annealing process, as illustrated in Fig.4, and TE performance was enhanced.…”

“…Fig.3. (color online) The in-plane transport mechanism of the (015)oriented Bi 1.5 Sb 0.5 Te 3 multilayered film with alternating stress field [63]. 3.1.2.…”