Berzins Andris, Grube Hugo, Sprugis Einars, Vaivars Guntars, Fescenko Ilja
Laser Center, University of Latvia, LV-1004 Riga, Latvia.
Institute of Solid State Physics, University of Latvia, LV-1063 Riga, Latvia.
Nanomaterials (Basel). 2022 Jun 29;12(13):2234. doi: 10.3390/nano12132234.
The implantation of diamonds with helium ions has become a common method to create hundreds-nanometers-thick near-surface layers of NV centers for high-sensitivity sensing and imaging applications; however, optimal implantation dose and annealing temperature are still a matter of discussion. In this study, we irradiated HPHT diamonds with an initial nitrogen concentration of 100 ppm using different implantation doses of helium ions to create 200-nm thick NV layers. We compare a previously considered optimal implantation dose of ∼1012 He+/cm2 to double and triple doses by measuring fluorescence intensity, contrast, and linewidth of magnetic resonances, as well as longitudinal and transversal relaxation times T1 and T2. From these direct measurements, we also estimate concentrations of P1 and NV centers. In addition, we compare the three diamond samples that underwent three consequent annealing steps to quantify the impact of processing at 1100 °C, which follows initial annealing at 800 °C. By tripling the implantation dose, we have increased the magnetic sensitivity of our sensors by 28±5%. By projecting our results to higher implantation doses, we demonstrate that it is possible to achieve a further improvement of up to 70%. At the same time, additional annealing steps at 1100 °C improve the sensitivity only by 6.6 ± 2.7%.
用氦离子注入钻石已成为一种常见方法，用于创建数百纳米厚的近表面NV中心层，以用于高灵敏度传感和成像应用；然而，最佳注入剂量和退火温度仍是一个有待探讨的问题。在本研究中，我们用不同剂量的氦离子辐照初始氮浓度为100 ppm的高温高压钻石，以创建200纳米厚的NV层。我们通过测量磁共振的荧光强度、对比度和线宽以及纵向和横向弛豫时间T1和T2，将先前认为的约1012 He+/cm2的最佳注入剂量与两倍和三倍剂量进行比较。从这些直接测量中，我们还估计了P1和NV中心的浓度。此外，我们比较了经过三个连续退火步骤的三个钻石样品，以量化在800℃初始退火后在1100℃进行处理的影响。通过将注入剂量增加两倍，我们将传感器的磁灵敏度提高了28±5%。通过将我们的结果推算到更高的注入剂量，我们证明有可能进一步提高高达70%。同时，在1100℃的额外退火步骤仅将灵敏度提高了6.6±2.7%。
