The conversion of neutral nitrogen-vacancy centers to negatively charged nitrogen-vacancy centers was demonstrated for centers created by ion implantation and annealing in high-purity diamond. Conversion occurred with surface exposure to an oxygen atmosphere at 465 C. The spectral properties of the charge-converted centers were investigated. Charge state control of nitrogen-vacancy centers close to the diamond surface was an important step toward the integration of these centers into devices for quantum information and magnetic sensing applications.

Conversion of Neutral Nitrogen-Vacancy Centers to Negatively Charged Nitrogen-Vacancy Centers Through Selective Oxidation. K.M.C.Fu, C.Santori, P.E.Barclay, R.G.Beausoleil: Applied Physics Letters, 2010, 96[12], 121907