Engineering shallow spins in diamond with nitrogen delta-doping

We demonstrate nanometer-precision depth control of nitrogen-vacancy (NV) center creation near the surface of synthetic diamond using an in situ nitrogen delta-doping technique during plasma-enhanced chemical vapor deposition. Despite their proximity to the surface, doped NV centers with depths (d) ranging from 5 to 100 nm display long spin coherence times, T-2>100 mu s at d = 5 nm and T-2>600 mu s at d >= 50 nm. The consistently long spin coherence observed in such shallow NV centers enables applications such as atomic-scale external spin sensing and hybrid quantum architectures. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4748280]