Enhanced optical absorption in conformally grown MoS₂layers on SiO₂/Si substrates with SiO₂nanopillars 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 SiO₂nanopillars (NPs) with a height of 50 nm on the optical characteristics of MoS₂layers is investigated. Using a metal organic chemical vapor deposition technique, a few layers of MoS₂were conformally grown on the NP-patterned SiO₂/Si substrates without notable strain. The photoluminescence and Raman intensities of the MoS₂layers on the SiO₂NPs were larger than those observed from a flat SiO₂surface. For 100 nm-SiO₂/Si wafers, the 50 nm-NP patterning enabled improved absorption in the MoS₂layers 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 MoS₂layers. These results suggest a versatile strategy to realize high-efficiency TMDC-based optoelectronic devices.