Preliminary studies on the formation of NV centers in nano-diamond

Johnson, B. C.; Sato, Shinichiro; Oshima, Takeshi; Simpson, D. A.*

Fluorescent nano-diamonds (NDs) are regarded as candidates for applications in bio-sensing, magnetometry and as hosts for single photon sources. There are a broad range of optically active centers in bulk diamond the most common being the NV center which can be manipulated at room temperature with electric, magnetic and microwave fields. The behavior of defects in NDs have been shown to be quite different than in the bulk. For example, N is known to be a stable doping impurity in bulk diamond while in NDs density functional theory simulations have predicted that it is metastable. This may partly explain the difficulty in the efficient fabrication of ultra-bright NDs. In this study, preliminary electron paramagnetic resonance (EPR) studies of N-related centers in nano-diamond of sizes between 15 and 100 nm is presented. The NDs have undergone various processing procedures including electron irradiation up to 2 MeV and subsequent annealing at 1000 C in order to convert from substitutional N atoms to NV centers.