In this paper, 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 a high density of states near Fermi level, the electronic conductivity is relative low because there is no carrier transport pathway along the a-axis direction. For n-type GeSe, a charge density channel is formed near conduction band minimum, 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.

本文利用第一原理和玻尔兹曼输运理论对p型和n型GeSe的热电性能进行了系统研究。计算内容包括电子结构、电子弛豫时间、晶格热导率和热电输运性质。结果表明，GeSe是一种间接带隙半导体，带隙为1.34 eV。虽然p型GeSe在费米能级附近具有较高的态密度，但由于沿a轴方向没有载流子传输路径，因此电子电导率相对较低。对于n型GeSe，在导带最小值附近形成电荷密度沟道，这提高了n型GeSe沿a轴方向的电导率。在700 K时，对于n型GeSe，最佳ZT值在4 × 10 ¹⁹ cm ^-3处达到2.5，而对于p型GeSe，最佳ZT值在1 × 10 ²⁰ cm ^-3处达到0.6。结果表明，n型GeSe比p型GeSe具有更好的热电性能，表明n型GeSe是一种很有前途的中温热电材料。