Decoration of nitrogen vacancies by oxygen atoms has been studied by near-edge X-ray absorption fine structure (NEXAFS) around B K-edge in several boron nitride (BN) structures, including bamboo-like and multi-walled BN nanotubes. Breaking of B–N bonds and formation of nitrogen vacancies under low-energy ion bombardment reduces oxidation resistance of BN structures and promotes an efficient oxygen-healing mechanism, in full agreement with some recent theoretical predictions. The formation of mixed O–B–N and B–O bonds is clearly identified by well-resolved peaks in NEXAFS spectra of excited boron atoms.

Formation of defects in hexagonal and cubic boron nitride ($h$ -BN and $c$ -BN, respectively) under low-energy argon or nitrogen ion-bombardment has been studied by near-edge x-ray absorption fine structure (NEXAFS) around boron and nitrogen $K$ -edges. Breaking of B–N bonds for both argon and nitrogen bombardment and formation of nitrogen vacancies, $V_{\text{N}}$ , has been identified from the $\text{B}K$ -edge of both $h$ -BN and $c$ -BN, followed by the formation of molecular nitrogen, ${\text{N}}_2$ , at interstitial positions. The presence of ${\text{N}}_2$ produces an additional peak in photoemission spectra around N $1s$ core level and a sharp resonance in the low-resolution NEXAFS spectra around $\text{N}K$ -edge, showing the characteristic vibrational fine structure in high-resolution measurements. In addition, several new peaks within the energy gap of BN, identified by NEXAFS around B and $\text{N}K$ -edges, have been assigned to boron or nitrogen interstitials, in good agreement with theoretical predictions. Ion bombardment destroys the cubic phase of $c$ -BN and produces a phase similar to a damaged hexagonal phase.