Luminescence Lifetimes of Neutral Nitrogen-Vacancy Centres in Synthetic Diamond Containing Nitrogen.

The decay time of luminescence from neutral nitrogen-vacancy (NV0) centres in synthetic diamond is reported. The intrinsic luminescence lifetime of NV0 is measured as tau(r) = 19 +/- 2 ns. Neutral substitutional nitrogen atoms. (N-s(0)) are shown to quench luminescence from NV0 by dipole-dipole resonant energy transfer at a rate such that the transfer time would equal tau(r) if one N-s(0) atom was similar to 3 nm from the NV0. In chemical-vapour-deposited diamonds grown with a small nitrogen content, that are brown as a result of vacancy-cluster defects, the decay time of NV0 equals tau(r) in the as-grown material. However, after annealing at >= 1700 degrees C to remove the brown colour, luminescence from the NV0 centres is severely quenched. This effect is suggested to be a result of the destruction of NV0 centres and the creation of new NV0 centres localized in vacancy-rich regions of the crystals.