Fracture-induced nanoscrolls from CVD-grown monolayer molybdenum disulfide

We report a simple and effective way of fabricating molybdenum disulfide (MoS₂) nanoscrolls by self-rolling up fractured monolayer CVD-grown MoS₂ microflakes. Morphological results reveal that MoS₂ nanoscrolls are formed only at newly formed edges, owing to an orientation-specific fracture behavior. Using Raman spectroscopy, we show that the E¹_2g Raman peak (A_1g peak) for MoS₂ nanoscrolls significantly red-shifts (blue-shifts), indicating structural change. The proposed mechanism is that the newly formed edges induced by fracture behavior self-roll up to nanoscrolls to minimize the surface free energy, meanwhile, the serious lattice contradiction of upper sulfur plane controls the rolling directions. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)