Thermoelectric properties of Zn doped Cu2SnSe3
Thermoelectric properties of Zn doped Cu2SnSe3
复制标题
DOI：
10.1016/j.matchemphys.2014.06.054
复制
发表时间：
2014-10-15
影响因子：
4.6
通讯作者：
Mallik, Ramesh Chandra
中科院分区：
文献类型：
--
作者：
Raju, Ch;Falmbigl, M.;Mallik, Ramesh Chandra
采用固相法合成了Zn掺杂的三元化合物Cu 2 ZnxSn 1-xSe 3（x = 0，0.025，0.05，0.075）。未掺杂的化合物显示单斜晶体结构作为主相，而掺杂的化合物显示立方晶体结构，这通过粉末XRD（X射线衍射）确认。采用扫描电镜（SEM）和电子探针（EPMA）对样品的表面形貌和元素组成进行了分析。热压样品的SEM显微照片显示存在连续和均匀的晶粒，证实了充分的致密化。所有样品的元素组成揭示了一个非化学计量比，这是由EPMA确定。在324 ~ 773 K之间测量了输运性质。电阻率在Cu 2 ZnxSn 1-xSe 3中降低至Zn含量x = 0.05的样品，并且在样品Cu2Zn0.075Sn0.925Se3中略微增加。这种行为与室温霍尔系数数据所证实的载流子浓度的变化是一致的。所有样品的电阻率随温度的变化表现出重掺杂半导体行为。所有样品均表现出正的Seebeck系数（S）和Hall系数，这表明大部分载流子是空穴。Seebeck系数随温度的增加呈线性增加，表明了半导体的简并行为。掺杂样品的总热导率随着掺杂量的增加而增加，这是由于载流子贡献的增加。所有样品的总热导率和晶格热导率均表现出1/1的依赖性，这表明在高温下声子散射占主导地位。最大的1/TZF = 0.48，在773 K时，获得的样品Cu 2SnSe 3由于低的热导率相比，掺杂的样品。(C)2014爱思唯尔有限公司版权所有。
Zn doped ternary compounds Cu2ZnxSn1-xSe3 (x = 0, 0.025, 0.05, 0.075) were prepared by solid state synthesis. The undoped compound showed a monoclinic crystal structure as a major phase, while the doped compounds showed a cubic crystal structure confirmed by powder XRD (X-Ray Diffraction). The surface morphology and elemental composition analysis for all the samples were studied by SEM (Scanning Electron Microscopy) and EPMA (Electron Probe Micro Analyzer), respectively. SEM micrographs of the hot pressed samples showed the presence of continuous and homogeneous grains confirming sufficient densification. Elemental composition of all the samples revealed an off-stoichiometry, which was determined by EPMA. Transport properties were measured between 324 K and 773 K. The electrical resistivity decreased up to the samples with Zn content x = 0.05 in Cu2ZnxSn1-xSe3, and slightly increased in the sample Cu2Zn0.075Sn0.925Se3. This behavior is consistent with the changes in the carrier concentration confirmed by room temperature Hall coefficient data. Temperature dependent electrical resistivity of all samples showed heavily doped semiconductor behavior. All the samples exhibit positive Seebeck coefficient (S) and Hall coefficient indicating that the majority of the carriers are holes. A linear increase in Seebeck coefficient with increase in temperature indicates the degenerate semiconductor behavior. The total thermal conductivity of the doped samples increased with a higher amount of doping, due to the increase in the carrier contribution. The total and lattice thermal conductivity of all samples showed 1/1 dependence, which points toward the dominance of phonon scattering at high temperatures. The maximum 1/TZF = 0.48 at 773 K was obtained for the sample Cu2SnSe3 due to a low thermal conductivity compared to the doped samples. (C) 2014 Elsevier B.V. All rights reserved.