2021/09/15 by Hyeongwoo Lee, Lee, Hyeongwoo, Yeonjeong Koo +21
Engineering · Materials Science · #2D Materials and Applications #Applied Physics (physics.app-ph) #FOS: Physical sciences #Graphene research and applications #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Perovskite Materials and Applications
paper · pdf · doi:10.48550/arxiv.2109.09713
openalex publication_date 2021/09/15 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Understanding and controlling the nanoscale transport of excitonic quasiparticles in atomically thin 2D semiconductors is crucial to produce highly efficient nano-excitonic devices. Here, we present a nano-gap device to selectively confine excitons or trions of 2D transition metal dichalcogenides at the nanoscale, facilitated by the drift-dominant exciton funnelling into the strain-induced local spot. We investigate the spatio-spectral characteristics of the funnelled excitons in a WSe2 monolayer (ML) and converted trions in a MoS2 ML using hyperspectral tip-enhanced photoluminescence (TEPL) imaging with <15 nm spatial resolution. In addition, we dynamically control the exciton funnelling and trion conversion rate by the GPa scale tip pressure engineering. Through a drift-diffusion model, we confirm an exciton funnelling efficiency of ~25 % with a significantly low strain threshold (~0.1 %) which sufficiently exceeds the efficiency of ~3 % in previous studies. This work provides a new strategy to facilitate efficient exciton transport and trion conversion of 2D semiconductor devices.