Luminescence in cubic boron nitride doped by rare‐earth impurity

Abstract We report shortly the observation of visible cathodoluminescence (CL) from micropowders of Eu‐doped cubic boron nitride synthesized under high‐pressure/high‐temperature conditions and also annealed in a vacuum in the temperature range from 400 to 1100 °C. The multiplet of lines due to the intra‐ 4f transitions on the Eu 3+ ion is detected in spectral region from 580 to 740 nm. The fact that the main line of the multiplet has the highest intensity, and the removed degeneracy of the 7 F 1 and 7 F 2 electronic levels represented by the second and third bands of the multiplet allow the conclusion that the red luminescence is due to the Eu 2 O 3 inclusions in the monoclinic form (probably, as nano particles) incorporated into the cBN grains. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)