Ultrafast‐Laser‐Induced Nanostructures with Continuously Tunable Period on Au Surface for Photoluminescence Control in Monolayer MoS2

Abstract

AbstractNanostructures of noble metal offer an exciting opportunity to tune photoluminescence (PL) in 2D materials, which has shown promise for applications in plasmonic devices. However, an efficient, designable, residue‐free nanofabrication method remains challenging. Herein, a one‐step ultrafast laser nanofabrication method is performed in fabrication of laser induced periodic surface structure (LIPSS) with continuously tunable periods over a wide range (from 439 to 2086 nm) on Au. The process of LIPSS imprinting is revealed at different time scales: periodical energy deposition within hundreds of femtoseconds, phase transition after 10 ps, and resolidification after 200 ps. Furthermore, the intensity and peak shift of PL in monolayer MoS2 (1L‐MoS2) can be tuned by LIPSS, 11‐fold enhancement resulting from nanoscale confinement of the incident laser and exciton‐trion localized interconversion emanating from hot electron transfer and tensile strain. The results are promising for 2D‐materials/metal heterostructures to applications in plasmonic devices and nanophotonic integrated circuits.