Tuning luminescence properties of hexagonal boron nitride with focused helium ion beam

Numerous diverse grown-in point defects in hexagonal boron nitride exhibit properties of single photon emitters stimulating the development of controllable methods for their local formation. In this work the defects created in hexagonal boron nitride by helium ion irradiation were investigated by means of cathodoluminescence and Raman spectroscopy. The irradiation with ion fluence above 10(15) cm(-2) resulted in a new Raman spectral band at about 1295 cm(-1), which can be attributed to the formation of vacancies or divacancies. The intensity of the defect-related luminescence was found to vary non-monotonically with ion fluence and possessed a maximum at about 10(14) cm(-2). On the basis of this result a new procedure to fabricate light emitting discs by means of the focused helium ion beam was suggested and demonstrated.