Two-dimensional transition-metal dichalcogenides exhibit rich excitonic properties. It is of great interest to achieve the modulation of the 2D semiconductor emission properties with spatial, spectral, polarization, and direction control. Plasmonic nanostructures can confine light to the nanoscale or even atomic scale and at the same time work as optical antennas to control light. Integrating plasmonic nanostructure with 2D semiconductor materials therefore has great potential in developing compact, high-performance photonic devices and nanoscale optoelectronic devices. In this presentation, we will introduce our recent work of employing individual plasmonic noble metal nanostructures to integrated with 2D WS2 and modulate the photoluminescence properties of the latter. We will first demonstrate the use of Au nanodisks and nanorods in generating and room-temperature detecting localized excitons of monolayer WS2 with defined spatial confinement and an energy shift up to 200 meV. We will then present the emission polarization and direction control of WS2 monolayer excitons by individual plasmonic nanoantennas. Besides the photoluminescence modulation of monolayer excitons, the plasmonic nanocrystals can form high-quality Fabry–Pérot resonators with integrating with WS2 flakes and a Au mirror, providing a platform for controlling the WS2 indirect band gap emissions.

Lei Shao is currently a professor in School of Electronics and Information Technology at Sun Yat-sen University. He obtained his Ph.D. in physics from The Chinese University of Hong Kong in 2013. Before joining Sun Yat-sen University, Dr. Shao did postdoctoral study at Chalmers University of Technology in Sweden from 2014 to 2017, joined The Chinese University of Hong Kong as a research assistant professor from 2017 to 2019, and then worked as an assistant professor in Beijing Computational Science Research Center from 2019 to 2022. Dr. Shao's research interest is focused on the study and development of novel nanophotonic structures and plasmonic optoelectronic devices. He has published over 85 papers in distinguished journals such as Nature, Nature Nanotechnology, Nature Communications, ACS Nano, Advanced Materials, etc., with a total citation of over 6000 times.