Department of Electrical Engineering & Computer Science, Case School of Engineering , Case Western Reserve University , 10900 Euclid Avenue , Cleveland , Ohio 44106 , United States.
Hefei National Laboratory for Physical Sciences at the Microscale and Department of Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China.
ACS Appl Mater Interfaces. 2018 Aug 1;10(30):25629-25637. doi: 10.1021/acsami.8b05408. Epub 2018 Jul 23.
Strong in-plane anisotropy of atomic layer and thin-film black phosphorus (P) offers new device perspectives and stimulates increasing interest and explorations, where precisely determining the black P crystal orientation and anisotropic axes is a necessity. Here, we demonstrate that the crystal orientation and intrinsic in-plane optical anisotropy of black P crystals in a broad thickness range (from ∼5 to ∼300 nm) can be directly and precisely determined, by polarized reflectance measurement alone, in visible range. Combining experiments with modeling of optical anisotropy and multilayer interference effects, we elucidate the underlying principles and validate these measurements. The polarized reflectance method is not only easy to implement but also deterministic, nondestructive, and effective for both on-substrate and suspended black P atomic layers and thin films.
体心四方相黑磷（P）具有较强的面内各向异性，为器件应用提供了新视角，激发了人们越来越多的兴趣和探索，而精确确定黑磷晶体的取向和各向异性轴则是前提。在此，我们证明了在较宽的厚度范围内（约 5nm 至 300nm），通过可见光波段的偏振反射测量，可直接且精确地确定黑磷晶体的取向和本征面内光学各向异性。通过与光学各向异性和多层干涉效应的建模相结合，我们阐明了其内在原理并验证了这些测量。偏振反射法不仅易于实施，而且对于基底上和悬浮的黑磷原子层和薄膜，它还是一种确定性、非破坏性且有效的方法。
