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Surface effects on nitrogen vacancy centers neutralization in diamond

MetadataDetails
Publication Date2016-11-11
JournalJournal of Applied Physics
AuthorsArthur N. Newell, Dontray A. Dowdell, D. H. Santamore
InstitutionsCenter for Astrophysics Harvard & Smithsonian, Delaware State University
Citations14

The performance of nitrogen vacancy (NVāˆ’) based magnetic sensors strongly depends on the stability of nitrogen vacancy centers near the diamond surface. The sensitivity of magnetic field detection is diminished as the NVāˆ’ turns into the neutralized charge state NV0. We investigate the neutralization of NVāˆ’ and calculate the ratio of NV0 to total NV (NVāˆ’+NV0) caused by a hydrogen terminated diamond with a surface water layer. We find that NVāˆ’ neutralization exhibits two distinct regions: near the surface, where the NVāˆ’ is completely neutralized, and in the bulk, where the neutralization ratio is inversely proportional to depth following the electrostatic force law. In addition, small changes in concentration can lead to large differences in neutralization behavior. This phenomenon allows one to carefully control the concentration to decrease the NVāˆ’ neutralization. The presence of nitrogen dopant greatly reduces NVāˆ’ neutralization as the nitrogen ionizes in preference to NVāˆ’ neutralization at the same depth. The water layer pH also affects neutralization. If the pH is very low due to cleaning agent residue, then we see a change in the band bending and the reduction of the two-dimensional hole gas region. Finally, we find that dissolved carbon dioxide resulting from direct contact with the atmosphere at room temperature hardly affects the NVāˆ’ neutralization.