Tunable Photoluminescence in WS2/WO3 Monolayer/Nanoparticles Hybrid Structure

Abstract

Photoluminescence (PL) of WS2 monolayer has attracted attention triggered by potential optoelectronic and photoelectric applications due to the largest direct band gap in WS2 monolayer among transition metal dichalcogenides. The PL of WS2 monolayer is dominated by charged excitons (trions) and bound excitons, which suppress the luminescence of free excitons. Herein, we report a one‐step growth of a nanosheet/nanoparticles hybrid structure to reduce the emission of bound excitons and trions in WS2 monolayer by surface passivation with WO3 nanoparticles. Peak positions of the PL spectra in WS2 monolayers depend on the density of WO3 nanoparticles on their surface. With increasing density of WO3 nanoparticles, the PL of WS2 monolayers experiences the transition from bound excitons and charged excitons (trions) to neutral excitons. These results suggest that the engineering of PL of WS2 monolayers may be realized by surface passivation using nanoparticles of wide band gap semiconductors.