Strong Anisotropic Optical Properties by Rolling up MoS₂ Nanoflake

Abstract

Although anisotropic two-dimensional materials have attracted great scientific interest, the anisotropy of those materials is limited to particular crystallographic directions. Herein, with dimension confining, MoS2 nanoscrolls are successfully fabricated by a rolling-up process after dropping an ethanol–water solution on a chemical vapor deposition-grown MoS2 monolayer. The anisotropic vibrational and optical properties are systematically studied by angle-resolved polarized spectroscopy, including Raman, photoluminescence, and reflection measurements. Upon comparing the photoluminescence results between MoS2 nanoscrolls and nanosheets, an obvious PL quenching phenomenon is observed, indicating the efficient separation of photon-induced carriers. Moreover, the time-resolved PL test identifying the lifetime of the carriers is decreased to 303 ps in the nanoscrolls, indicating a higher carrier-transfer efficiency. In summary, our work demonstrates the strong anisotropic optical properties of MoS2 nanorolls, showing the nanoscrolls are a promising candidate for the fabrication of multifunctional devices.