[11p-M113-1~20] 6.2 Carbon-based thin films

[11p-M113-8] Surface oxidation and electron-spin coherence of nitrogen-vacancy centers
in nanodiamonds

〇Masazumi Fujiwara^1,2, Ryuta Tsukahara¹, Yoshihiko Sera¹, Yushi Nishimura², Yuko Sugai¹, Christian Jentgens³, Yoshio Teki², Shinichi Shikata¹, Hideki Hashimoto¹ (1.Kwansei Gakuin Univ., 2.Osaka City Univ., 3.Microdiamant AG)

Keywords:Nanodiamond, Electron spin

We present a systematic study on the relation between the surface oxidation and T₂ of single NV centers in NDs. We apply aerobic and acidic oxidation methods with various heating temperatures and processing times and found that aerobic oxidation most effectively oxidizes the surface and extends T₂ by a factor of 1.6 to the original NDs. The ND-size dependence of T₂ clearly shows that the surface oxidation removes a constant decoherence contribution irrespective of the ND size and that a new surface-derived decoherence source emerges when the ND size reduces below 50 nm.