Excitonic absorption and defect-related emission in three-dimensional MoS 2 pyramids.

MoS 2 micro-pyramids have demonstrated interesting properties in the fields of photonics and non-linear optics. In this work, we show the excitonic absorption and cathodoluminescence (CL) emission of MoS 2 micro-pyramids grown by chemical vapor deposition (CVD) on SiO 2 substrates. The excitonic absorption was obtained at room and cryogenic temperatures by taking advantage of the cathodoluminescence emission of the SiO 2 substrate. We detected the CL emission related to defect intra-gap states, localized at the pyramid edges and with an enhanced intensity at the pyramid basal vertices. The photoluminescence and absorption analysis provided the Stokes shift of both the A and B excitons in the MoS 2 pyramids. This analysis provides new insights into the optical functionality of MoS 2 pyramids. This method can be applied to other 3D structures within the 2D materials family.