Nitrogen vacancy luminescence and their phonon sidebands characteristics in nitrogen-doped diamond

In this work, the nitrogen vacancy (NV) luminescence properties and their phonon sidebands in both high and low nitrogen diamonds after electron irradiation and subsequent annealing were thoroughly investigated. From the extracted results, it was demonstrated that the phonon sidebands were caused by the phonon emission behavior of the electrons located in the NV center during the induced transition process from the laser excitation. On top of that, the phonon energies of the NV⁰ (neutral) and NV^— (negatively charged) centers were estimated at about 45 meV and 63 meV, respectively. As the measurement temperature increased, the excited electrons were more likely to return to the ground state by employing non-radiative transitions without generating phonon sidebands. As a result, the synchronous quenching of the NV luminescence and their phonon sidebands effect takes place. The complex lattice environment of the NV centers in the high nitrogen diamond leads also to a smaller thermal quenching activation energy, while the phonon process at a relatively high measurement temperature results in the manifestation of more obvious phonon sidebands of the NV centers.