Formation of optical centers in CVD diamond by electron and neutron irradiation

An investigation of the formation of optical centers in chemical vapor deposited diamond (CVD diamond) by electron and neutron irradiation has been carried out. Cathodoluminescence was mainly used for observation of the optical centers. Several optical centers have been observed after the irradiation and subsequent annealing at 900°C, such as the 5RL center and the centers with zero-phonon lines at 3.19 eV, 2.16 eV and 1.94 eV. Because these centers are considered to have relations to nitrogen atoms, vacancies or interstitials, it is expected that their luminescence intensities depend on the amount of nitrogen doping and radiation dose. However, decrease in the luminescence intensity with the amount of nitrogen doping has been observed. Boron-doped specimens have also been irradiated and annealed, but the formation of defects related to boron has not been observed.