Ultrahigh nitrogen-vacancy center concentration in diamond
Ultrahigh nitrogen-vacancy center concentration in diamond
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DOI：
10.1016/j.carbon.2021.12.032
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发表时间：
2021-10
期刊：
影响因子：
10.9
通讯作者：
S. Kollarics;F. Simon;A. Bojtor;K. Koltai;G. Klujber;M. Szieberth;B. G. M'arkus;D. Beke;K. Kamar'as;Á. Gali;D. Amirari;R. Berry;S. Boucher;D. Gavryushkin;G. Jeschke;J. P. Cleveland;S. Takahashi;P. Szirmai;L. Forr'o;E. Emmanouilidou;R. Singh;K. Holczer
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作者：
S. Kollarics;F. Simon;A. Bojtor;K. Koltai;G. Klujber;M. Szieberth;B. G. M'arkus;D. Beke;K. Kamar'as;Á. Gali;D. Amirari;R. Berry;S. Boucher;D. Gavryushkin;G. Jeschke;J. P. Cleveland;S. Takahashi;P. Szirmai;L. Forr'o;E. Emmanouilidou;R. Singh;K. Holczer
使用电子和中子照射以及随后的逐步热退火，在含有约100 ppm氮的金刚石单晶中产生高浓度的带负电荷的氮空位（NV-）中心。连续波电子顺磁共振（EPR）被用来确定从孤立的N原子到NV−中心在每个生产步骤的转换效率，其最高值高达17.5%。电子辐照后形成的电荷空位所示的EPR谱，但热退火恢复样品的质量作为缺陷信号减弱。我们发现在退火过程中约有25%的空位形成了NVs。大的NV−浓度允许观察取向相关的自旋弛豫时间，并使用电子自旋回波（ESE）和电子-核双共振（ENDOR）高精度地确定超精细和四极耦合常数。我们还观察到EPR信号与所谓的W16中心，其光谱特性可能意味着氮二聚体空位中心的起源。
High concentration of negatively charged nitrogen-vacancy (NV−) centers was created in diamond single crystals containing approximately 100 ppm nitrogen using electron and neutron irradiation and subsequent thermal annealing in a stepwise manner. Continuous-wave electron paramagnetic resonance (EPR) was used to determine the transformation efficiency from isolated N atoms to NV−centers in each production step and its highest value was as high as 17.5%. Charged vacancies are formed after electron irradiation as shown by EPR spectra, but the thermal annealing restores the sample quality as the defect signal diminishes. We find that about 25% of the vacancies form NVs during the annealing process. The large NV−concentration allows observing orientation dependent spin-relaxation times and also determining the hyperfine and quadrupole coupling constants with high precision using electron spin echo (ESE) and electron-nuclear double resonance (ENDOR). We also observed the EPR signal associated with the so-called W16 centers, whose spectroscopic properties might imply a nitrogen dimer-vacancy center for its origin.