Scattering Properties of MoS₂ Edges and Folds Using Darkfield Hyperspectral Microscopy

Abstract

The optical characteristics of one-dimensional (1D) MoS 2 edges and folds at the grain level, acting as interfaces in diverse optoelectronic applications, remain unexplored in contrast to the basal plane. In this study, we utilize dark-field hyperspectral microscopy (DFHM) to investigate the optical properties of individual edges and folds in MoS 2 synthesized by chemical vapor deposition. Through DFHM, spatiospectral scattering information about these features is acquired. Comparative analysis with complementary reflection hyperspectral microscopy reveals red shifts in transitions on the edge spectrum of single-layered MoS 2 , regardless of the edge types, attributed to lattice strain and edge defects. Deconvolution of the edge spectrum unveils an increased contribution from the indirect band gap. The polarized DFHM experiment exhibits 1D scattering behavior along edges. An increase in the number of MoS 2 layers leads to a reduction in the degree of red shift and the intensity of the scatter, correlated with the decreased roughness of the edge surface. Additionally, MoS 2 folds also exhibited scattering behaviors influenced by the twisted bilayer structure. The DFHM method will be a valuable approach to gain insights into the structure−property relationships at the interfaces of various low-dimensional nanomaterials.