Enhanced optical absorption in conformally grown MoS 2 layers on SiO 2 /Si substrates with SiO 2 nanopillars with a height of 50 nm.

The integration of transition metal dichalcogenide (TMDC) layers on nanostructures has attracted growing attention as a means to improve the physical properties of the ultrathin TMDC materials. In this work, the influence of SiO 2 nanopillars (NPs) with a height of 50 nm on the optical characteristics of MoS 2 layers is investigated. Using a metal organic chemical vapor deposition technique, a few layers of MoS 2 were conformally grown on the NP-patterned SiO 2 /Si substrates without notable strain. The photoluminescence and Raman intensities of the MoS 2 layers on the SiO 2 NPs were larger than those observed from a flat SiO 2 surface. For 100 nm-SiO 2 /Si wafers, the 50 nm-NP patterning enabled improved absorption in the MoS 2 layers over the whole visible wavelength range. Optical simulations showed that a strong electric-field could be formed at the NP surface, which led to the enhanced absorption in the MoS 2 layers. These results suggest a versatile strategy to realize high-efficiency TMDC-based optoelectronic devices.