金刚石集群NV色心的光谱特征及浓度定量分析

金刚石NV-色心具有优越的光致发光特性，可实现高灵敏度物理量探测。其中，NV-色心的浓度是影响其宏观领域物理量探测灵敏度的重要因素之一。分析了金刚石在NV-色心制备过程中产生的发光缺陷，研究了不同的电子注入剂量与NV-色心浓度的关系。首先，对金刚石进行电子辐照并高温真空退火，制备了NV-色心；然后，利用拉曼光谱仪测试了金刚石在电子辐照前、电子辐照后及退火后三个阶段中的荧光光谱，分析了金刚石在NV-色心制备过程中的光谱特性；最后，对生成的NV-色心的浓度进行了估算，并探究了不同电子注入剂量对NV-色心浓度的影响规律。结果表明，金刚石经电子注入后生成了524.7，541.1，578和648.1 nm发光中心。其中，HPHT合成金刚石经电子注入后普遍存在524.7 nm中心。电子注入后的金刚石经高温(≥800 ℃)真空(≥10-7 Pa)退火后，空位自由移动，不稳定的缺陷消失，当空位靠近氮原子时被束缚而形成氮空位色心。对于氮含量100 ppm的金刚石，当电子注入产生的空位含量小于120 ppm(2.1×1019 cm-3)时，NV-色心浓度与电子注入生成空位的含量的关系符合Boltzmann分布。该研究为利用氮含量100 ppm的金刚石实现定量NV-色心浓度的制备提供了参考依据，为NV-色心在宏观物理量精密测量的应用奠定了基础。

Spectral Characteristics and Concentration Quantitative Analysis of NV Center Ensembles in Diamond

Nitrogen-vacancy (NV-) centers of diamond can realize the function of high-sensitivity physical quantity detection with superior photo-luminescence properties.The concentration of NV-centers is one of the main factors that affect the physical quantity detection sensitivity in the macro field.The paper studied and analyzed the relationship between different electron injection doses and the concentrations of NV-centers.The research method was carried out as follows: firstly,diamonds were exposed to electron irradiation and further subjected to high temperature annealing in vacuum in order to prepare NV-centers;then,a Raman spectrometer was utilized to test the fluorescence spectra of diamond in the following three stages: before and after electron irradiation,and after annealing,so that the Raman spectral characteristic of diamond was analyzed during the NV-center preparation process;finally,the concentrations of the prepared NV-centers were estimated,and the influence rules of different electron injection doses on the concentrations of the NV-centers were also explored.The results show that after electron injection is performed on diamond,luminescence defects of 524.7,541.1,578 and 648.1 nm are formed,wherein centers of 524.7 nm are commonly found in HPHT synthetic diamond subjected to electron injection.After annealing at high temperature (≥800 ℃) in vacuum (≥10-7 Pa) is performed on diamond subjected to electron injection,vacancies move freely,the unstable defects disappear,and nitrogen-vacancy centers are formed when the vacancies are bound while moving close to nitrogen atoms.For diamond with a nitrogen content of 100 ppm,the relationship between the concentrations of NV-centers and the electron injection dose was in line with Boltzmann distribution when the number of vacancies produced with electron injection is smaller than 120 ppm (2.1×1019 cm-3).This study provides a reference basis for quantitative preparation of NV-centers by utilizing diamond with the nitrogen content of 100 ppm,and further lays a foundation for application of NV-centers to precision macroscopic physical quantity measurement.