First-Principles Simulations Correlating X-ray Absorption Spectroscopy Features to Point Defects in h-BN

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Hexagonal boron nitride (h-BN) is a key material for advanced electronics, quantum information technology, and energy storage.
• Soft X-ray absorption spectroscopy (XAS) provides atomic-level insights into BN materials, particularly defects.
• Accurate correlation between XAS spectra and specific defect types in h-BN is currently lacking.

Purpose of the Study:

• To elucidate the origins of unique spectroscopic features in sputter-deposited turbostratic h-BN films.
• To correlate specific defect-related peaks in B K-edge XAS spectra with atomic and electronic structures.
• To understand the role of impurities and passivation in h-BN defect properties.

Main Methods:

• B K-edge X-ray absorption spectroscopy (XAS) measurements on sputter-deposited turbostratic h-BN films.
• First-principles spectroscopic simulations to analyze electronic structure.
• Detailed analysis of local charge transfer characteristics associated with defects.

Main Results:

• Identified two main defect-related peaks in the XAS spectra of h-BN films.
• Associated these peaks with electronic states of H-passivated B atoms bonded to one and two oxygen impurity atoms.
• Distinguished these defect peaks from the main π* resonances of h-BN and B2O3.

Conclusions:

• The study successfully correlates specific XAS spectral features with H-passivated B atoms bonded to oxygen impurities in h-BN.
• These findings are critical for understanding and controlling defect-mediated properties in h-BN for technological applications.
• Provides a pathway for precise defect characterization in h-BN using XAS.