Thin-film metallic glass: an effective diffusion barrier for Se-doped AgSbTe2thermoelectric modules.
The thermal stability of joints in thermoelectric (TE) modules, which are degraded during interdiffusion between the TE material and the contacting metal, needs to be addressed in order to utilize TE technology for competitive, sustainable energy applications. Herein, we deposit a 200 nm-thick Zr-based thin-film metallic glass (TFMG), which acts as an effective diffusion barrier layer with low electrical contact resistivity, on a high-zT Se-doped AgSbTe2substrate. The reaction couples structured with TFMG/TE are annealed at 673 K for 8-360 hours and analyzed by electron microscopy. No observable IMCs (intermetallic compounds) are formed at the TFMG/TE interface, suggesting the effective inhibition of atomic diffusion that may be attributed to the grain-boundary-free structure of TFMG. The minor amount of Se acts as a tracer species, and a homogeneous Se-rich region is found nearing the TFMG/TE interface, which guarantees satisfactory bonding at the joint. The diffusion of Se, which has the smallest atomic volume of all the elements from the TE substrate, is found to follow Fick's second law. The calculated diffusivity (D) of Se in TFMG falls in the range of D~10-20-10-23(m2/s), which is 106~107and 1012~1013times smaller than those of Ni [10-14-10-17(m2/s)] and Cu [10-8-10-11(m2/s)] in Bi2Te3, respectively.
Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
Chia-Chi
CC
Yu
Department of Materials and Optoelectronic science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
Hsin-Jay
HJ
Wu
Department of Materials and Optoelectronic science, National Sun Yat-sen University, Kaohsiung 80424, Taiwan.
Ping-Yuan
PY
Deng
Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.
Matthias T
MT
Agne
Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA.
G Jeffrey
GJ
Snyder
Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan.
Jinn P
JP
Chu