Journal of Inorganic Materials, Volume. 37, Issue 2, 209(2022)
MnTe is a promising candidate for the p-type lead-free thermoelectric material in middle temperature application. However, its thermoelectric performance isn’t qualified for some conventional n-type materials to form efficient thermoelectric devices. In this study, Mn1.06-xGexTe (x=0, 0.01, 0.02, 0.03, 0.04) polycrystalline block samples with different Ge doping contents were efficiently synthesized by vacuum melting quenching and spark plasma sintering. The as-obtained Mn1.06-xGexTe bulk was dense and consisted of homogeneous composition. Tiny extensive Mn can effectively restrict the formation of the second phase of MnTe2 and improve the thermoelectric properties of the matrix phase. Electrical conductivity of the materials increasing to 7×103S∙cm-1 results from the enhanced carrier concentration 7.328×1018 cm-3 at 873 K, which contributed to a power factor of 620 μW∙m -1∙K-2 by 4% Ge doping. Meanwhile, Mn1.06-xGexTe showed the reduced thermal conductivity of 0.62 W∙m-1∙K-1 by enhanced phonons scattering intensified with point defects, realizing the effective regulation of both electrical- and thermal-transport properties. Mn1.02Ge0.04Te achieved a thermoelectric performance of 0.86 at 873 K, which evolved by 43% compared with the pristine sample.
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Xunuo LOU, Houquan DENG, Shuang LI, Qingtang ZHANG, Wenjie XIONG, Guodong TANG.
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Received: Dec. 24, 2020
Accepted: --
Published Online: Nov. 14, 2022
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