Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA.
Lehrstuhl für Theoretische Physik, Universität Paderborn, Warburger Str. 100, 33098 Paderborn, Germany.
J Chem Phys. 2019 Apr 7;150(13):134702. doi: 10.1063/1.5085351.
Nanodiamonds (NDs) hosting nitrogen-vacancy (NV) centers are a promising platform for quantum sensing applications. Sensitivity of the applications using NV centers in NDs is often limited due to the presence of paramagnetic impurity contents near the ND surface. Here, we investigate near-surface paramagnetic impurities in NDs. Using high-frequency (HF) electron paramagnetic resonance spectroscopy, the near-surface paramagnetic impurity within the shell of NDs is probed and its g-value is determined to be 2.0028(3). Furthermore, HF electron-electron double resonance-detected nuclear magnetic resonance spectroscopy and a first principles calculation show that a possible structure of the near-surface impurity is the negatively charged vacancy V. The identification of the near-surface impurity by the present investigation provides a promising pathway to improve the NV properties in NDs and the NV-based sensing techniques.
纳米金刚石（NDs）中含有氮空位（NV）中心，是量子传感应用的一个很有前途的平台。由于 ND 表面附近存在顺磁杂质含量，因此使用 NV 中心的应用的灵敏度通常受到限制。在这里，我们研究了 NDs 中的近表面顺磁杂质。使用高频（HF）电子顺磁共振波谱技术，探测了 ND 壳层内的近表面顺磁杂质，并确定其 g 值为 2.0028(3)。此外，HF 电子-电子双共振检测核磁共振波谱和第一性原理计算表明，近表面杂质的一种可能结构是带负电荷的空位 V。本研究中对近表面杂质的鉴定为改善 NDs 中 NV 特性和基于 NV 的传感技术提供了一条很有前途的途径。
