Fig. 1: Optical properties of neutron-irradiated monoisotopic hBN crystals.

a Raman scattering spectra recorded at room temperature on the h11BN (red dots) and h10BN crystals (blue dots) after neutron irradiation. The solid lines are data fitting with Lorentzian functions. b Typical lateral PL raster scan of the h10BN crystals under green laser illumination with a power of 1 mW. c Axial confocal scan showing a high PL signal localized at the crystal surfaces. d PL spectra recorded from the h11BN (red) and h10BN crystals (blue). The data have been normalized and vertically shifted for the sake of clarity.