Photoluminescence enhancement and ultrafast relaxation dynamics in a low-dimensional heterostructure: effect of plasmon–exciton coupling

Abstract

In this work, we present an in-depth study on a low-dimensional heterostructure comprising monolayer (ML) tungsten disulfide (WS₂) and 1D plasmonic photonic crystal (PPC). Stable-state photoluminescence (PL) experiments are employed to study the optical properties of WS₂ films with and without PPC. In addition, angle-resolved reflectance and PL microscopy measurements are used to identify the coupling effects between ML WS₂ and 1D PPC. Furthermore, by means of femtosecond pump-probe experiments, the relaxation time for the newly proposed heterostructure is extracted to be 0.74 ps and 21.9 ps. Importantly, the underlying mechanism of the relaxation processes is also revealed in the hybrid for the first time, to the best of our knowledge.