Hexagonal Boron Nitride Spin Defects for Quantum Photonics: Annealing-Free Generation by Krypton Ion Implantation

arXiv:2606.23334 — Hexagonal Boron Nitride Spin Defects for Quantum Photonics: Annealing-Free Generation by Krypton Ion Implantation. Shyam, Ikshvaku, Singh, Raj, Akkanaboina, Mangababu, Sonawane, A. M. et al..

Ion Implantation Methodology

The study introduces krypton ion ($\mathrm{Kr}^+$) implantation as a method to create luminescent defects in hexagonal boron nitride (hBN). This technique operates at room temperature and does not require any annealing steps, simplifying the fabrication process.

Using 40 keV $\mathrm{Kr}^+$ ions, the researchers optimized the implantation parameters through SRIM Monte Carlo simulations, which guided the effective generation of defect centers.

• No pre- or post-implantation annealing required
• Stable luminescence at $\mathrm{~830 nm}$
• Fluence range: $10^{11}$–$10^{15}\ \mathrm{ions/cm}^{2}$

Photoluminescence Characteristics

The implanted hBN samples exhibited a stable near-infrared photoluminescence band centered around $\mathrm{~830 nm}$. The intensity of this luminescence increased with higher implantation fluences, indicating a direct correlation between the number of ions and defect formation.

Temperature-dependent measurements showed a linewidth broadening that follows a $T^{3}$ temperature dependence, suggesting that acoustic phonons play a significant role in the dephasing of the luminescent states.

• Photoluminescence intensity increases with fluence
• Broadening consistent with acoustic-phonon interactions

Defect Characterization

Raman spectroscopy confirmed the presence of implantation-induced defects alongside the characteristic modes of pristine hBN. The $E_{2g}$ mode was observed at $\mathrm{~1366 cm}^{-1}$, with a defect feature at $\mathrm{~1295 cm}^{-1}$.

Electron paramagnetic resonance (EPR) measurements identified a paramagnetic center with a $g$-factor of $2.003$, supporting the formation of a $V_{\mathrm{N}}$–$C_{\mathrm{B}}$ donor-acceptor pair complex as the source of the optical and magnetic properties.

• Raman modes confirm defect presence
• EPR reveals paramagnetic centers

Implications for Quantum Photonics

This annealing-free method of generating luminescent defects in hBN presents a scalable approach for developing quantum photonic devices. The ability to produce stable defects at room temperature is crucial for practical applications in quantum technologies.

The findings suggest that the integration of these defects into quantum systems could enhance performance and reliability, making them a valuable asset for future research and development.

• Scalable defect generation method
• Potential for improved quantum device performance

Takeaway

Krypton ion implantation offers a promising, simplified approach to creating luminescent defects in hBN, paving the way for advancements in quantum photonics.

• Annealing-free process simplifies defect generation
• Stable luminescence enhances quantum technology prospects
• Room-temperature operation is a key advantage

Reference: arXiv:2606.23334 · Hexagonal Boron Nitride Spin Defects for Quantum Photonics: Annealing-Free Generation by Krypton Ion Implantation