Ionizing radiation induced strain engineering for exciton dynamics in atomically thin semiconductor

Uncovering and manipulating the dynamics of exciton resided in atomically thin layer under external stimulation is cornerstone for excitonic devices, which demonstrates significant potential for overcoming challenges related to response time and integration in electronic, photonic, or hybrid systems. Although ionizing radiation possess advantages including non-contact, non-reagent doping, technical maturity, and low-cost for modulating exciton dynamics, conventional irradiation techniques often compromise devices integrity through defect generation or irreversible doping. Here we demonstrate a non-destructive strain-engineering strategy using low-energy (≤1000 eV) alpha-particle irradiation in monolayer semiconductors. The alpha-particle irradiation can induce helium accumulation between WSe 2 monolayer and substrates, forming nanobubbles without causing defects, which can be controllably aggregated into larger ones through annealing. The nanobubbles can induce an exciton funneling effect that enhances photoluminescence (PL) intensity and a spectral red shift. Moreover, nanobubble-induced strain gradient amplifies the potential disorder of monolayer, causing stronger exciton localization and higher optimal temperature for exciton emission and transport. These findings highlight the significant potential of controllable ionizing radiation for on-demand modulation of 2D exciton dynamics through strain engineering induced by nanobubbles, laying an important foundation for applications in high-performance sensing, energy harvesting, and quantum information processing.