Programmable Nanowrinkle-Induced Room-Temperature Exciton Localization in Monolayer WSe2

TL;DR

This paper demonstrates a method to intentionally induce and control nanowrinkles in monolayer WSe2, creating localized exciton emitters at room temperature, advancing quantum emission applications in 2D materials.

Contribution

It introduces a patterned array technique to generate and control nanowrinkles, linking wrinkle properties to exciton localization, and reveals the heterogeneity of strain environments around stressors.

Findings

Controlled wrinkle direction and position via patterned arrays.

Localized exciton emission confined to < 10 nm regions.

Heterogeneous strain environment around stressors.

Abstract

Localized states in two-dimensional (2D) transition metal dichalcogenides (TMDCs) have been the subject of intense study, driven by potential applications in quantum information science. Despite the rapidly growing knowledge surrounding these emitters, their microscopic nature is still not fully understood, limiting their production and application. Motivated by this challenge, and by recent theoretical and experimental evidence showing that nanowrinkles generate localized room-temperature emitters, we demonstrate a method to intentionally induce wrinkles with collections of stressors, showing that long-range wrinkle direction and position are controllable with patterned array design. Nano-photoluminescence (nano-PL) imaging combined with detailed strain modeling based on measured wrinkle topography establishes a correlation between wrinkle properties, particularly shear strain, and localized exciton emission. Beyond the array-induced super-wrinkles, nano-PL spatial maps further reveal that the strain environment around individual stressors is heterogeneous due to the presence of fine wrinkles that are less deterministic. Detailed nanoscale hyperspectral images uncover a wide range of low-energy emission peaks originating from these fine wrinkles, and show that the states can be tightly confined to regions < 10 nm, even in ambient conditions. These results establish a promising potential route towards realizing room temperature quantum emission in 2D TMDC systems.