Symposium EL08: Emerging Material Platforms and Fundamental Approaches for Plasmonics, Nanophotonics and Metasurfaces

Tony Heinz, Professor of Applied Physics and Photon Science at Stanford University

Properties and Control of Excitons in 2D Semiconductor Heterostructures

Written by Matthew Nakamura

Tony Heinz from Stanford University presented his group’s work on insights into excitons in 2D heterostructures, specifically in transition metal dichalcogenides. In these systems, stacked layers result in a type II band alignment, leading to interlayer excitons as the lowest-lying optical excited state. Notably, the static dipole moment of these charge-separated states allows for high tunability through external electric fields, offering a unique source with adjustable photon energy in visible and infrared spectra. Crystallographically aligned samples introduce distinctive exciton localization effects due to moiré potential. Heinz showcased recent progress in characterizing these states through optical absorption measurements and time-resolved, angle-resolved photoemission spectroscopy. The research sheds light on radiative lifetimes and the nature of exciton localization in moiré structures. Heinz emphasized the convergence of 2D materials and meta-optics, highlighting their complementary roles in providing precise control over materials excitations. The integration of these exciting fields holds significant potential for advancing optical research and a wide array of applications.