Optical studies of nickel complexes in high pressure synthetic diamond

摘要

We report uniaxial stress measurements on the 2.242 eV photoinced zero phonon line, observed on nickel- and nitrogen-containing synthetic diamonds after annealing at 1600 deg C. We show that the line is an electric dipole transition, which occurs at a defect of rhombic I symmetry. The shape of the vibronic sideband and the temperature dependence of the line position and width can be understood assuming electron-phonon coupling to totally symmetric vibrational modes centred at h omega= 55 meV. Electron-lattice interaction cannot explain the large decrease of ZPL intensity with temperature, and it is suggested that some thermal activated de-excitation path is responsible for the observed behaviour.