Nanoscale Manipulation of Exciton–Trion Interconversion in a MoSe₂ Monolayer via Tip-Enhanced Cavity-Spectroscopy

Abstract

Emerging light–matter interactions in metal–semiconductor hybrid platforms have attracted considerable attention due to their potential applications in optoelectronic devices. Here, we demonstrate plasmon-induced near-field manipulation of trionic responses in a MoSe 2 monolayer using tip-enhanced cavity-spectroscopy (TECS). The surface plasmon–polariton mode on the Au nanowire can locally manipulate the exciton (X 0 ) and trion (X-) populations of MoSe 2 . Furthermore, we reveal that surface charges significantly influence the emission and interconversion processes of X 0 and X-. In the TECS configuration, the localized plasmon significantly affects the distributions of X 0 and X- due to the modified radiative decay rate. Additionally, within the TECS cavity, the electric doping effect and hot electron generation enable dynamic interconversion between X 0 and X- at the nanoscale. This work advances our understanding of plasmon–exciton–hot electron interactions in metal–semiconductor–metal hybrid structures, providing a foundation for an optimal trion-based nano-optoelectronic platform.