High Density, Localized Quantum Emitters in Strained 2D Semiconductors

TL;DR

This paper presents a scalable, lithography-free method to create high-density, localized quantum emitters in WSe2 monolayers by inducing strain with nanoparticle arrays, advancing quantum light source development.

Contribution

A novel bottom-up approach using nanoparticle arrays to produce high-density quantum emitters in 2D semiconductors without lithography.

Findings

Achieved ~150 emitters/μm² in WSe2 monolayers.

Demonstrated strain-induced localized states emitting single photons.

Showed tunability and scalability of quantum emitters.

Abstract

Two-dimensional chalcogenide semiconductors have recently emerged as a host material for quantum emitters of single photons. While several reports on defect and strain-induced single photon emission from 2D chalcogenides exist, a bottom-up, lithography-free approach to producing a high density of emitters remains elusive. Further, the physical properties of quantum emission in the case of strained 2D semiconductors are far from being understood. Here, we demonstrate a bottom-up, scalable, and lithography-free approach to creating large areas of localized emitters with high density (~150 emitters/um2) in a WSe2 monolayer. We induce strain inside the WSe2 monolayer with high spatial density by conformally placing the WSe2 monolayer over a uniform array of Pt nanoparticles with a size of 10 nm. Cryogenic, time-resolved, and gate-tunable luminescence measurements combined with near-field luminescence spectroscopy suggest the formation of localized states in strained regions that emit single photons with a high spatial density. Our approach of using a metal nanoparticle array to generate a high density of strained quantum emitters opens a new path towards scalable, tunable, and versatile quantum light sources.