Annealing effects on the morphology and luminescence of cubic boron nitride based ceramics

Formation of flower-like MgO crystal and its effect on the photoluminescence of Mg-cBN ceramics

“…To explore the potential direct doping of cBN ceramics using Mg as a possible substitute of beryllium, cBN ceramics with addition of Mg were sintered under high temperature and high pressure conditions, followed by post-annealing treatment. During the post-annealing process, Mg is highly possible to be oxidized even only trace amount of oxygen in the annealing atmosphere, which is similar to Si doped cBN ceramics investigated in our previous work [27].…”

“…4(a)). According to our previous research [27], the peak near 317 nm, similarly, could be derived from the oxygen vacancies in cBN grains by scavenging of O from cBN grains by the added Mg. In this paper, upon annealing the 317 nm peak intensity is very low.…”

Effects of Carbon and Oxygen Impurities on Luminescence Properties of BCNO Phosphor

“…Although there are no carbon and oxygen elements in RM, oxidation is evidently inevitable in preparing S 1 sample; therefore, both excitation and emission spectra are originated from B‐, N‐, and O‐related defects. The 215‐nm (~5.7 eV) excitation is corresponding to the band gap transition of BN, and the 280‐nm (~4.4 eV) excitation is likely to be correlated with intrinsic defects of BN such as N vacancy, whereas the 350 nm (~3.5 eV) excitation may be correlated with the oxygen‐related defects in BN …”

“…The 215-nm (~5.7 eV) excitation is corresponding to the band gap transition of BN, and the 280-nm (~4.4 eV) excitation is likely to be correlated with intrinsic defects of BN such as N vacancy, whereas the 350 nm (~3.5 eV) excitation may be correlated with the oxygen-related defects in BN. [21][22][23] Figure 3 shows the excitation and emission spectra of S 2 sample using boric acid and urea as RM. As there are carbon elements in urea and oxygen elements in boric acid, the effects of carbon and oxygen cannot be ruled out for S 2 sample.…”