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Anisotropy Control–Induced Unique Anisotropic Thermoelectric Performance in the n‐Type Bi 2 Te 2.7 Se 0.3 Thin Films
Author(s) -
Tan Ming,
Liu WeiDi,
Shi XiaoLei,
Gao Han,
Li Hui,
Li Cong,
Liu XiaoBiao,
Deng Yuan,
Chen ZhiGang
Publication year - 2019
Publication title -
small methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.66
H-Index - 46
ISSN - 2366-9608
DOI - 10.1002/smtd.201900582
Subject(s) - anisotropy , thermoelectric effect , condensed matter physics , electric field , materials science , figure of merit , electrical resistivity and conductivity , thermal conductivity , optoelectronics , optics , physics , composite material , thermodynamics , quantum mechanics
Anisotropic Bi 2 Te 3 ‐based thermoelectric materials have drawn extensive interest in the past decades. Here, n‐type Bi 2 Te 2.7 Se 0.3 films with superhigh figure of merit are developed through anisotropy control via tuning an external electric field and deposition anisotropy. It is found that the angle of interplanar grain boundaries between (0 1 5) and (0 1 11) planes can be tuned by the applied external electric field, which leads to the strengthened anisotropy of electron mobility and simultaneously maintains low lattice thermal conductivity. Dominated by the unique change in the anisotropy of both lattice thermal conductivity and electron mobility, a record‐high zT value of ≈1.6 at room temperature can be achieved in the as‐deposited n‐type Bi 2 Te 2.7 Se 0.3 film under 20 V external electric field. This work indicates that the electric field–induced deposition anisotropy control can be used to develop high‐performance Bi 2 Te 3 ‐based thermoelectric films.