Effect of proton irradiation on the cathodoluminescence of gallium nitride films

In this work, we studied the effect of 350 keV proton irradiation with two different fluences of 1013 cm−2 and 1015 cm−2 on the cathodoluminescence (CL) spectrum of GaN. Three lines were observed in the CL spectra of virgin and proton pre-irradiated samples - band edge line (3.4 eV), blue line (2.8 eV) and yellow line (2.15 eV). A strong decrease in the CL intensity for samples pre-irradiated by protons, especially at high proton fluence of 1015 cm−2, is shown. The evolution of the cathodoluminescence spectra during electron irradiation demonstrates a further decrease in all line intensities. It was shown that virgin and proton pre-irradiated GaN samples were not charged under electron irradiation. The cathodoluminescence signal drop can be caused by a decrease in the concentration of initial luminescence centers associated with intrinsic and impurity defects due to their transformation under proton bombardment and electron-stimulated diffusion implanted H+ ions. •Cathodoluminescence of GaN films after proton irradiation is investigated.•Proton implantation significantly reduces the cathodoluminescence intensity.•Cathodoluminescence intensity deceases with increasing electron irradiation fluence.•GaN samples are not charged under electron irradiation.