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Preparation and Thermoelectric Properties of Zn‐Doped Sn‐Based Type‐VIII Single‐Crystalline Clathrate via a Grey Sn‐Flux Method
Author(s) -
Shen Lanxian,
Li Decong,
Deng Shuping,
Tang Yu,
Chen Zhong,
Liu Zuming,
Yang Peizhi,
Deng Shukang
Publication year - 2018
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201700150
Subject(s) - analytical chemistry (journal) , flux method , endothermic process , flux (metallurgy) , doping , thermoelectric effect , clathrate hydrate , seebeck coefficient , chemistry , electrical resistivity and conductivity , conduction band , materials science , crystallography , hydrate , single crystal , adsorption , metallurgy , thermodynamics , electron , organic chemistry , electrical engineering , engineering , physics , optoelectronics , chromatography , quantum mechanics
A single‐crystalline samples of Zn‐substituted type‐VIII clathrate Ba 8 Ga 16 Sn 30 with n‐type carriers by α ‐Sn flux method according to the formula Ba 8 Ga 16 Zn x Sn 30 ( x = 0, 0.5, 1, and 1.5) is grown. It is found that as the amount of Zn increases from 0.025 to 0.155, the content of Ga decreases from 15.18 to 14.72, indicating Zn atoms preferentially replacing Ga. The carrier concentrations of obtained samples vary from 3.55 × 10 19 to 5.53 × 10 19 cm −3 as carrier mobility changes from 14.7 to 20.9 cm 2 · V −1 · s −1 at room temperature. Meanwhile, the endothermic peak temperature for all samples is approximately 519 °C, which is slightly lower than that of the previous experimental reported. For all samples, their effective mass m */ m 0 are lower than that prepared by β ‐Sn, indicating that the band structure near the conduction band minima is affected. As a result, the sample with x = 1.5 obtains the higher power factor with the maximum value of 1.07 × 10 −3 W m −1 K −2 at 568 K and the largest ZT value of 0.63 at 537 K.