Insights into the Nature of Quantum Emitters in Electron-Irradiated hexagonal Boron Nitride

TL;DR

This study clarifies the origin of quantum emitters in electron-irradiated hexagonal boron nitride, demonstrating they are intrinsic defects, not contaminants, and explores their stability and creation in ultra-thin layers for quantum applications.

Contribution

It provides a comprehensive framework to distinguish intrinsic quantum emitters in hBN from contamination and demonstrates controlled creation of stable emitters in ultra-thin hBN layers.

Findings

Organic contamination is ruled out as the source of emission.

Stable quantum emitters can be created in hBN layers below 10 nm thick.

The emitters show spectral variability and thermal stability.

Abstract

Quantum emitters in hexagonal boron nitride (hBN) have emerged as a promising solid-state platform for quantum technology applications. However, a persistent challenge in the field is the unclear origin of many observed emission lines, particularly in the visible range, which can be difficult to distinguish from signals arising from organic or process-induced contamination during sample preparations and handling. This ambiguity limits both the reproducibility of emitter generation and the reliable identification of truly intrinsic quantum defects. This work provides a step-by-step framework to assess whether quantum emitters in electron-irradiated hBN are associated with organic contaminants introduced during sample preparation. We employ hyperspectral imaging, thermal annealing, and oxygen plasma etching to investigate the origin of the green-yellow emitters in electron-irradiated hBN. The combined results not only rule out organic contamination as the source of emission but also provide insight into the spectral variability, thermal stability, and vertical localization of the emitters generated in electron-irradiated hBN that was created without any pre- or post-processing. In addition, our experiments demonstrate the feasibility of creating stable emitters in hBN with thicknesses below 10 nm. These findings provide practical guidance for the identification and controlled implementation of hBN-based single-photon emitters in quantum photonic devices.