Abstract
We report a study on the optical luminescence properties and the electronic structures of boron nitride nanotubes (BNNTs). BNNTs with natural B (80% B-11 and 20% B-10) and pure B-10 are investigated in comparison with hexagonal BN crystals using X-ray absorption near-edge structures (XANES) and X-ray excited optical luminescence (XEOL). We find that the BNNT specimen synthesized with natural B contains more oxide impurities than that with pure B-10, resulting in significantly different behavior in optical luminescence. All BN samples with hexagonal structures are found to emit strong luminescence, but the emission spectra are strongly morphology- and structure dependent XEOL and XANES measurements were carried out at the B K-edge, N K-edge, and O K-edge in order to reveal the origin of different luminescence channels and the corresponding, electronic structures in these BN materials.