Structured-Defect Engineering of Hexagonal Boron Nitride for Identified Visible Single-Photon Emitters

Area of Science:

• Materials Science
• Quantum Optics
• 2D Materials

Background:

• Hexagonal boron nitride (hBN) single-photon emitters (SPEs) show promise for quantum optical technologies due to their visible-range emission.
• Controlling carbon defect structures in hBN for uniform band structure is crucial for on-chip quantum device integration but remains challenging.

Purpose of the Study:

• To demonstrate precise control over hBN SPE emission by engineering carbon defect structures.
• To investigate the conversion of carbon defects from CB to C2B-CN and its effect on optical properties.

Main Methods:

• Chemical Vapor Deposition (CVD) process with controlled carbon concentrations (0.0005–0.082 at %) in Copper (Cu) substrates.
• Density Functional Theory (DFT) calculations to analyze band structure, vibrational modes, and electronic transitions.
• Spectroscopic analysis of SPE emission, focusing on zero-phonon line (ZPL) shifts.

Main Results:

• Successfully engineered carbon defects in hBN, converting from CB to C2B-CN by regulating carbon concentration during CVD.
• Achieved a precise shift in the zero-phonon line (ZPL) of SPEs from 600–610 nm to 630–640 nm.
• DFT results confirmed the correlation between defect structure changes, band structure modifications, and observed spectral shifts.

Conclusions:

• Demonstrated structured defect engineering in hBN for tailored emission properties of SPEs.
• SPE emission spectra can serve as a fingerprint for identifying changes in carbon point defect structures.
• This work highlights the potential of 2D material engineering for advanced on-chip quantum devices.