Decay rate statistics of NV centres in diamond on plasmonic and dielectric substrates

We study experimentally the statistics of the emission characteristics of NV0 centres in diamond nanoparticles in different dielectric environments. Diamond nanoparticleswith sizes of ~120 nm each containing a large number of NV centres (>1000) are deposited on different substrates, including dielectrics (silicon, silicon nitride, diamond) and plasmonic metals (silver). We record lifetime and emission spectra by time-resolved cathodoluminescence (TR-CL). For each different substrate we collect data from 60 different clusters of particles and study the statistics of their emission properties. We observe a strong variation of the lifetime statistics in different substrates, with the shortest average decay rate and narrowest distribution occurring in the case of diamond substrate. On the other hand, plasmonic (Ag) and high index dielectric (Si) substrate result in longer lifetimes and substantially broader distributions. Our results provide insights into the role of the dielectric environment and indicate the presence of complex interactions with the substrate