Mapping the location and configuration of nitrogen in diamond nanoparticles

Understanding how impurities such as nitrogen are included in diamond nanoparticles is expected to be important for use in future nanodevices, such as qubits for quantum computing. Most commercial diamond nanoparticles contain approximately 2-3% nitrogen, but it is difficult to determine experimentally whether it is located within the core or at the surface of the nanoparticles. Presented here are density functional tight-binding simulations examining the configuration and potential energy surface of substitutional nitrogen in diamond nanoparticles, directly comparing results of different sizes, shapes and surface chemistry. The results predict that nitrogen is metastable within the core of both hydrogenated and dehydrogenated particles, but that the binding energy, coordination and preferred location is dependent upon the structure of the nanoparticle as a whole.