High-temperature charge and thermal transport properties of the n-type thermoelectric material PbSe
High-temperature charge and thermal transport properties of the n-type thermoelectric material PbSe
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DOI：
10.1103/physrevb.84.155207
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发表时间：
2011-10-18
影响因子：
3.7
通讯作者：
Kanatzidis, Mercouri G.
中科院分区：
文献类型：
--
作者：
Androulakis, John;Chung, Duck-Young;Kanatzidis, Mercouri G.
本文详细研究了n型PbSe晶体的电荷输运、红外光学反射率和热输运性质。在500 K以上的温度下，一种强散射、迁移率限制机制被揭示出来。该机制是复杂的电子-声子相互作用，不能单独用传统的声学声子散射解释的指示。我们应用一阶非抛物线近似提取了室温和700 K下态密度有效质量随掺杂的变化关系。的结果进行了比较，抛物线带模型和掺杂依赖的红外光学反射率的研究。作为温度的函数的热导率行为显示出与预期的Debye-Peierls高温行为（umklapp为主）的强烈偏离，表明额外的载热通道，我们将其与光学声子激发相关联。的热导率观测的高温载流子迁移率行为的相关性进行了讨论。热电优值在700 K时在1.5 x 10（19）cm（-3）附近显示出类似于0.8的有希望的值。
We present a detailed study of the charge transport, infrared optical reflectivity, and thermal transport properties of n-type PbSe crystals. A strong scattering, mobility-limiting mechanism was revealed to be at play at temperatures above 500 K. The mechanism is indicative of complex electron-phonon interactions that cannot be explained by conventional acoustic phonon scattering alone. We applied the first-order nonparabolicity approximation to extract the density-of-states effective mass as a function of doping both at room temperature and at 700 K. The results are compared to those of a parabolic band model and in light of doping-dependent studies of the infrared optical reflectivity. The thermal conductivity behavior as a function of temperature shows a strong deviation from the expected Debye-Peierls high-temperature behavior (umklapp dominated) indicating an additional heat-carrying channel, which we associate with optical phonon excitations. The correlation of the thermal conductivity observations to the high-temperature carrier mobility behavior is discussed. The thermoelectric figure of merit exhibits a promising value of similar to 0.8 at 700 K at similar to 1.5 x 10(19) cm(-3).