講演情報
[25a-12H-5]12C-enriched fluorescent nanodiamonds prepared from CVD-grown diamond
〇(D)Mina Tavakkoli1, Keisuke Oshimi1, Takaki Arakawa1, Tokuyuki Teraji2, Masazumi Fujiwara1 (1.Okayama Univ., 2.NIMS)
キーワード：
nanodiamond、NV spin properties
Nanodiamonds containing fluorescent nitrogen-vacancy (NV) centers exhibit optically-detected magnetic resonance (ODMR) at room temperature. Various physical and chemical quantities such as magnetic field, temperature, and associated chemical parameters of pH and magnetic ions can be measured by recording spectral shift of ODMR or changes in spin relaxation rates in pulsed ODMR experiments. Recently, we have reported bulk-limited NV spin coherence in ultrabright 12C-enriched nanodiamonds (NDs) that were milled from HPHT grown single crystalline diamonds where major spin impurities of N and 13C were reduced [1]. However, the large-scale production of 12C-enriched NDs in a resource-efficient manner particularly for 12C-enriched methane is still required for further biochemical applications, as batch reactions for the surface functionalization of NDs require more than 10 mg of NDs to obtain higher yields.
In this study, we pursue efficient production of 12C-enriched NDs using chemical vapor deposition (CVD) method. We prepared 12C-enriched polycrystalline diamonds using CVD method [2] with a growth protocol for efficient conversion from methane to diamond [3]. Subsequently, the synthesized microdiamonds were milled to NDs. The obtained NDs were first chemically cleaned by boiling acid to remove graphitic components, followed by oxidized by aerobic heat treatment and centrifuged for size fraction (Fig. 1a,b). We prepared five sample batches and compared the luminescence index. We then selected the brightest batch for the further spin characterization by ODMR, including spin echo measurements (Fig. 1c).
In this study, we pursue efficient production of 12C-enriched NDs using chemical vapor deposition (CVD) method. We prepared 12C-enriched polycrystalline diamonds using CVD method [2] with a growth protocol for efficient conversion from methane to diamond [3]. Subsequently, the synthesized microdiamonds were milled to NDs. The obtained NDs were first chemically cleaned by boiling acid to remove graphitic components, followed by oxidized by aerobic heat treatment and centrifuged for size fraction (Fig. 1a,b). We prepared five sample batches and compared the luminescence index. We then selected the brightest batch for the further spin characterization by ODMR, including spin echo measurements (Fig. 1c).