Color centers with reproducible spectral characteristics in hexagonal boron nitride (hBN) irradiated with protons

The possibility of reproducible creation of optically active centers in hexagonal boron nitride (hBN) in the visible and near infrared ranges by irradiating hBN with high-energy protons (15 MeV) was investigated. It was shown that such irradiation leads to the appearance of a set of narrow zero-phonon lines (ZPL) with wavelengths $\lambda_{\mathrm{ZPL1}}$ = 533.3 nm, $\lambda_{\mathrm{ZPL2}}$ = 542.6 nm, $\lambda_{\mathrm{ZPL3}}$ = 542.6 nm in the visible range of the micro-photoluminescence spectrum upon excitation by a laser with $\lambda$ = 514 nm and a temperature $T$ = 12 K. In this case, the zero-phonon line $\lambda_{\mathrm{ZPL1}}$ is also observed at room temperature with a maximum intensity at a wavelength of $\lambda_{\mathrm{ZPL1}}$ = 534.9 nm. Along with these lines, the photoluminescence spectrum contains a band in the near IR range, corresponding to a negatively charged boron vacancy $(V_{\mathrm{B}}^-)$.