Presence and distribution of impurity defects in crystalline cubic boron nitride. A spectroscopic study

• Published in: Radiation measurements 2019-04, Vol.123, p.21-25
• Main Authors: Nistor, S.V., Nistor, L.C., Joita, A.C., Vlaicu, A.M.
• Format: Article
• Language: English
• Subjects: Cathodoluminscence; Cubic boron nitride; Electron spin resonance; Impurities; Photoluminescence; Scanning electron microscopy
• ISSN: 1350-4487; 1879-0925
• DOI: 10.1016/j.radmeas.2019.02.003

The results of the present Q-band electron spin resonance (ESR) investigation on amber colored cubic boron nitride (cBN) crystalline superabrasive powder (BORAZON CBN400) offer further support to the hypothesis that impurity ions with high natural abundant zero nuclear spin isotopes, distributed non-uniformly, are involved in the structure of the observed paramagnetic centers. One could thus explain the absence of any hyperfine structure in the multifrequency electron spin resonance spectra of both presently and previously investigated cBN crystalline powders and single crystals. The scanning electron microscopy, cathodoluminescence and photoluminescence studies performed on single crystallites selected from the same cBN400 batch further confirm the presence of electro- and photo-luminescent active impurity related centers, non-uniformly distributed in the cBN crystallite host lattice. The observation of an intense and reproducible thermoluminescence spectrum, up to high radiation doses, attributed to several trapping centers involving impurities, is also reported here. •ESR spectra of point defects in crystalline cBN do not exhibit hyperfine structure.•Suggested presence of impurities with natural abundant zero nuclear spin isotopes.•Observed non-uniform distributed electro-and photo-luminescent centers.•Linear and reproducible thermoluminescence response up to 62 Gy maximum dose.