Schué Léonard, Goudreault Félix A, Righi Ariete, Resende Geovani C, Lefebvre Valérie, Godbout Émile, Tie Monique, Ribeiro Henrique B, Heinz Tony F, Pimenta Marcos A, Côté Michel, Francœur Sébastien, Martel Richard
Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
Département de Physique, Université de Montréal, Montréal, Québec H3C 3J7, Canada.
Nano Lett. 2022 Apr 13;22(7):2851-2858. doi: 10.1021/acs.nanolett.1c04998. Epub 2022 Mar 21.
Black phosphorus (BP) is unique among layered materials because of its homonuclear lattice and strong structural anisotropy. While recent investigations on few-layer BP have extensively explored the in-plane (, ) anisotropy, much less attention has been given to the out-of-plane direction (). Here, the optical response from bulk BP is probed using polarization-resolved photoluminescence (PL), photoluminescence excitation (PLE), and resonant Raman scattering along the zigzag, out-of-plane, and armchair directions. An unexpected -polarized luminescence emission is detected in the visible, far above the fundamental gap. PLE indicates that this emission is generated through -polarized excitation at 2.3 eV. The same electronic resonance is observed in resonant Raman with the enhancement of the A phonon modes scattering efficiency. These experimental results are fully consistent with DFT calculations of the permittivity tensor elements and demonstrate the remarkable extent to which the anisotropy influences the optical properties and carrier dynamics in black phosphorus.
黑磷（BP）在层状材料中独具特色，因其具有同核晶格和强烈的结构各向异性。尽管近期对少层BP的研究广泛探讨了面内（，）各向异性，但对垂直于平面方向（）的关注却少得多。在此，通过沿锯齿形、垂直于平面以及扶手椅形方向的偏振分辨光致发光（PL）、光致发光激发（PLE）和共振拉曼散射，对体相BP的光学响应进行了探测。在可见光范围内检测到了意想不到的 - 偏振发光发射，远高于本征能隙。PLE表明这种发射是通过2.3 eV的 - 偏振激发产生的。在共振拉曼中观察到相同的电子共振，同时A声子模式散射效率增强。这些实验结果与介电常数张量元素的密度泛函理论（DFT）计算完全一致，并证明了各向异性对黑磷光学性质和载流子动力学影响的显著程度。
