We report on the noise spectrum experienced by few nanometer deep nitrogen-vacancy centers in diamond as a function of depth, surface coating, magnetic field and temperature. Analysis reveals a double-Lorentzian noise spectra consistent with a surfac
e electronic spin bath, with slower dynamics due to spin-spin interactions and faster dynamics related to phononic coupling. These results shed new light on the mechanisms responsible for surface noise affecting shallow spins at semiconductor interfaces, and suggests possible directions for further studies. We demonstrate dynamical decoupling from the surface noise, paving the way to applications ranging from nanoscale NMR to quantum networks.
