Room-temperature Raman and photoluminescence spectra, photo-current and thermally stimulated current were measured in order to investigate the mid-gap defects in diamonds grown by using a hot-filament chemical vapour deposition technique. The [Si–V]0 centres caused by the Si–C bonds in diamond grains and at grain boundaries were located at 1.68eV. The level at 1.55eV was first detected by using photoluminescence, and was tentatively attributed to the zero-phonon luminescence line or vibronic band of the [Si-V]0 induced by the Si-O bonds. The 2.7 to 3.2eV and 1.9 to 2.1eV photo-current peaks were detected. The [N–V] complex could be related to these defect levels. Some shallow energy levels, lower than 1.0eV, were also observed in the CVD diamond.

Characterization of Defects in Chemical Vapour Deposited Diamonds. M.L.Zhang, Y.B.Xia, L.J.Wang, B.B.Gu: Chinese Physics Letters, 2005, 22[1], 1264-6