High-Throughput Production of an Atomically Thin Nano-Dot Array for Enhanced Exciton-Exciton Interactions

Monolayer transition metal dichalcogenides (TMDs) are an appealing material platform for investigating and manipulating excitonic properties in the atomically thin limit due to their intrinsic strong Coulomb interactions and alleviated screening effects. To date, a number of such studies have been conducted to determine the excitonic physics or control their dynamics by diverse experimental approaches including electrostatic gating, magnetic field manipulation and strain engineering. However, physically confined excitonic transport through nanostructuring is not handled yet. Herein, we introduce a high-throughput nanofabrication of laterally confined monolayer TMDs in a hexagonal array. The fabricated nanodots of monolayer TMDs are approximately 20 nm wide far below typical exciton diffusion length of monolayer TMDs. We then investigated their photoluminescence (PL) characteristics by performing a series of power, wavelength (2.25~2.82 eV), and temperature dependent measurements. We observed the unconventional emission in sub-20 nm WS₂ nanodots, which is presumably associated with the physically confined excitonic transport behavior and reconstructed band structure. This platform is suitable tool for understanding of confined quasi-particle transport behavior and size-dependent PL study, providing a broader insight for fundamental excitonic many-body interactions and related dynamics.