Anisotropic Electron-Photon and Electron-Phonon Interactions in Black Phosphorus
Anisotropic Electron-Photon and Electron-Phonon Interactions in Black Phosphorus
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DOI：
10.1021/acs.nanolett.5b04540
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发表时间：
2016-04-01
期刊：
影响因子：
10.8
通讯作者：
Dresselhaus, Mildred S.
中科院分区：
文献类型：
--
作者：
Ling, Xi;Huang, Shengxi;Dresselhaus, Mildred S.
正交黑磷（BP）和其他层状材料，例如碲化镓（GaTe）和硒化锡（SnSe），由于它们的各向异性面内结构而在二维（2D）材料中脱颖而出。这种各向异性为2D材料的特性增加了一个新的维度，并刺激了角度分辨光子学和电子学的发展。然而，理解各向异性的影响至今仍不令人满意，如在最近的文献中的一些不一致所示。我们利用角分辨吸收和拉曼光谱研究了各向异性对BP中电子-光子和电子-声子相互作用的影响。我们强调，实验和理论上，各向异性和薄片厚度和光子和声子能量之间的非平凡的依赖。我们表明，一旦理解，各向异性的光学吸收似乎是一个可靠的和简单的方式来确定BP的结晶取向，这不能确定从拉曼光谱没有明确考虑的激发波长和薄片厚度，如以前常用的。
Orthorhombic black phosphorus (BP) and other layered materials, such as gallium telluride (GaTe) and tin selenide (SnSe), stand out among two-dimensional (2D) materials owing to their anisotropic in-plane structure. This anisotropy adds a new dimension to the properties of 2D materials and stimulates the development of angle-resolved photonics and electronics. However, understanding the effect of anisotropy has remained unsatisfactory to date, as shown by a number of inconsistencies in the recent literature. We use angle-resolved absorption and Raman spectroscopies to investigate the role of anisotropy on the electron photon and electron phonon interactions in BP. We highlight, both experimentally and theoretically, a nontrivial dependence between anisotropy and flake thickness and photon and phonon energies. We show that once understood, the anisotropic optical absorption appears to be a reliable and simple way to identify the crystalline orientation of BP, which cannot be determined from Raman spectroscopy without the explicit consideration of excitation wavelength and flake thickness, as commonly used previously.