摘要:通过密度泛函理论、GW方法和Bethe-Salpter方程,我们探讨了磷的同素异形体单层(黑磷单层和蓝磷单层)的电子结构和光吸收。计算表明:黑磷单层是直接带隙的半导体且带隙约为1.91eV,可以被利用在光、电子方面;蓝磷单层是个间接带隙的半导体,其带隙为3.49eV。更有趣的是,黑磷单层有高度各项异性的光吸收,蓝磷单层有各项同性的光吸收。且它们有可观的激子束缚能,黑磷单层约为830meV,蓝磷约为760meV。这些结果为黑磷和蓝磷单层在电子和光电子方面的应用提供有价值的指导。
关键词:蓝磷;黑磷;密度泛函理论;GW方法;能量带隙;光吸收
Abstract:By means of density functional theory, GW method and Bethe-Salpter equation, we discuss the electronic structure and optical absorption of monolayer black phosphorus and blue phosphorus. The calculations show that the black phosphorus monolayer is a direct bandgap semiconductor with a band gap of about 1.91 eV, which can be used in optoelectronics; the blue phosphorus monolayer is an indirect bandgap semiconductor with a band gap of about 3.49 eV. More interestingly, the black phosphorus monolayer has a highly anisotropic optical absorption, however, blue phosphorus monolayer has a isotropic opticalabsorption. And they both have considerable exciton binding energy, where is 830 meV for black phosphorus and 760 meV for blue phosphorus, respectively. These results provide valuable guidance for the application of black and blue phosphorus monolayers in electronics and optoelectronics.
Keywords: Black phosphorus; blue phosphorus; GW method; density functional theory; bandgap; optical absorption
目录
第一章绪论 1
1.1引言 1
1.2石墨烯简介 1
1.3二硫化钼简介 2
1.4黑磷简介 2
1.4.1黑磷电子结构 3
1.4.2黑磷单层电子和光学性质的调谐 4
1.4.3黑磷的相关应用 4
1.5蓝磷简介 5
第二章理论背景 6
2.1薛定谔方程和两个基本近似 7
2.2密度泛函理论 7
2.2.1 Thomas-Feimi-Direc模型 7
2.2.2 Hohenberg-Kohn定理 7
2.2.3 Kohn-Sham方程 8
2.2.4交换关联能泛函 9
2.3多体微扰理论 10
2.3.1准粒子 10
2.3.2Bathe-Salpeter方程和光吸收 11
2.4本文涉及的软件包简介 12
2.4.1Quantum-ESPRESSO 12
2.4.2Yambo软件包 13
第三章磷同素异形体单层的电子结构与光学性质 14
3.1研究背景 14
3.2计算模型与方法 14
3.3结果与讨论 16
本章小结 20
结论 21
致谢 22
参考文献