@article{0eb8ab9827da47868a8bb6b8bcdf6439,
title = "Removing Non-Size-Dependent Electron Spin Decoherence of Nanodiamond Quantum Sensors by Aerobic Oxidation",
abstract = "Surface oxidation of nanodiamonds (NDs) is a primary step of their surface functionalization that is key to the success of their recent emerging applications in nanoscale quantum sensors in biological samples. Here, we investigate how the electron spin coherence of single nitrogen vacancy centers in NDs is extended by two major oxidizing techniques, that is, aerobic oxidation and anaerobic triacid oxidation with various processing parameters. Aerobic oxidation at 550 °C most effectively oxidizes the surface and extends T2 by a factor of 1.44 ± 0.33 to the original NDs. The ND size dependence of this T2 extension shows that aerobic oxidation removes a constant decoherence contribution irrespective of the ND size, which clearly separates its origin from the surface-derived decoherence sources. The present results highlight the presence of the ND-specific decoherence sources other than surface termination spin noise and spin-active impurities, thereby improving the spin coherence of ND quantum sensors.",
keywords = "coherence, nanodiamond, nitrogen vacancy center, oxidation, surface functionalization",
author = "Ryuta Tsukahara and Masazumi Fujiwara and Yoshihiko Sera and Yushi Nishimura and Yuko Sugai and Christian Jentgens and Yoshio Teki and Hideki Hashimoto and Shinichi Shikata",
note = "Funding Information: We thank Prof. Noboru Ohtani for the AFM measurements, Mr. Keisuke Oshimi for the computational support of T2 measurements, and HORIBA Inc. for the Raman measurements. We also thank Dr. Akihiro Shimizu for the help with XPS measurements. A part of this study was conducted at Hokkaido University and Chitose Institute of Science and Technology, supported by “Nanotechnology Platform” Program of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. M.F. acknowledges the financial support provided by JSPS-KAKENHI (Nos. 26706007, 26610077, 16K13646, and 17H02741), MEXT-LEADER program, and Osaka City University (OCU-Strategic Research Grant 2017 & 2018 for young researchers and top-priority research). S.S. acknowledges the financial support provided by JSPS-KAKENHI (No. 26220602). H.H. thanks JSPS KAKENHI, Grant-in-Aid for Basic Research (B) (No. 16H04181) and Scientific Research on Innovative Areas “Innovations for Light-Energy Conversion (I4LEC)” (Nos. 17H06433, 17H0637) for the financial support. Publisher Copyright: {\textcopyright} 2019 American Chemical Society.",
year = "2019",
month = jun,
day = "28",
doi = "10.1021/acsanm.9b00614",
language = "English",
volume = "2",
pages = "3701--3710",
journal = "ACS Applied Nano Materials",
issn = "2574-0970",
publisher = "American Chemical Society",
number = "6",
}