Thermoelectric performances for both p- and n- type GeSe

The thermoelectric properties of p-type and n-type GeSe are studied systematically by using first principles and Boltzmann transport theory. The calculation includes electronic structure, electron relaxation time, lattice thermal conductivity and thermoelectric transport properties. The results show that GeSe is an indirect band gap semiconductor with band gap 1.34 eV. Though p-type GeSe has high density of states near Fermi level, the electronic conductivity is relative low because there is no carrier transport pathway along a-axis direction. For n-type GeSe, a charge density channel is formed near CBM, which improves the electrical conductivity of n-type GeSe along the a-axis direction. At 700 K, the optimal ZT value reaches 2.5 at 4×1019 cm-3 for n-type GeSe, while that is 0.6 at 1×1020 cm-3 for p-type GeSe. The results show n-type GeSe has better thermoelectric properties than p-type GeSe, indicating that n-type GeSe is a promising thermoelectric material in middle temperature.

The data include electronic structure, electron relaxation time, lattice thermal conductivity and thermoelectric transport properties for p- and n-type GeSe.

Methods
First principles and Boltzmann transport theory.

本研究采用第一性原理（first principles）与玻尔兹曼输运理论（Boltzmann transport theory），系统探究了p型与n型硒化锗（GeSe）的热电性能。本次计算涵盖电子结构、电子弛豫时间（electron relaxation time）、晶格热导率（lattice thermal conductivity）以及热电输运性能。研究结果表明，硒化锗为间接带隙半导体，带隙宽度为1.34 eV。尽管p型硒化锗在费米能级（Fermi level）附近具有较高的态密度，但由于沿a轴方向不存在载流子输运通道，其电子电导率相对较低。对于n型硒化锗，在导带底（conduction band minimum, CBM）附近形成了电荷密度通道，提升了其沿a轴方向的电子电导率。在700 K时，n型硒化锗在载流子浓度为4×10^19 cm^-3时取得最优热电优值（ZT）2.5，而p型硒化锗在载流子浓度为1×10^20 cm^-3时的最优ZT值为0.6。上述结果表明，n型硒化锗的热电性能优于p型硒化锗，说明n型硒化锗是一种极具应用前景的中温热电材料。

本数据集涵盖p型与n型硒化锗的电子结构、电子弛豫时间、晶格热导率以及热电输运性能数据。

研究方法：第一性原理与玻尔兹曼输运理论。