In diamond, nitrogen defects like the substitutional nitrogen defect $\left({\mathrm{N}}_{\mathrm{s}}\right)$ or the nitrogen-vacancy-hydrogen complex (NVH) outnumber the nitrogen-vacancy (NV) defect by at least one order of magnitude creating a dense spin bath. While neutral ${\mathrm{N}}_{\mathrm{s}}$ has an impact on the coherence of the NV spin state, the atomic structure of NVH reminds of a NV center decorated with a hydrogen atom. As a consequence, the formation of NVH centers could compete with that of NV centers possibly lowering the N-to-NV conversion efficiency in diamond grown with hydrogen-plasma-assisted chemical vapor deposition (CVD). Therefore, monitoring and controlling the spin bath is essential to produce and understand engineered diamond material with high NV concentrations for quantum applications. While the incorporation of ${\mathrm{N}}_{\mathrm{s}}$ in diamond has been investigated on the nano- and mesoscale for years, studies concerning the influence of CVD parameters and the crystal orientation on the NVH formation have been restricted to bulk N-doped diamond providing high-enough spin numbers for electron paramagnetic resonance and optical absorption spectroscopy techniques. Here, we investigate submicron-thick (100)-diamond layers with nitrogen contents of $(13.8\pm 1.6)\mathrm{ppm}$ and $(16.7\pm 3.6)\mathrm{ppm}$, and exploiting the NV centers in the layers as local nanosensors, we demonstrate the detection of ${}^{}{\mathrm{NVH}}^{-}$ centers using double electron-electron resonance (DEER). To determine the ${}^{}{\mathrm{NVH}}^{-}$ densities, we quantitatively fit the hyperfine structure of ${}^{}{\mathrm{NVH}}^{-}$ and confirm the results with the DEER method usually used for determining ${}^{}{{\mathrm{N}}_{\mathrm{s}}}^0$ densities. With our experiments, we access the spin bath composition on the nanoscale and enable a fast feedback loop in CVD recipe optimization with thin diamond layers instead of resource- and time-intensive bulk crystals. Furthermore, the quantification of ${}^{}{\mathrm{NVH}}^{-}$ plays a very important role for understanding the dynamics of vacancies and the incorporation of hydrogen into CVD diamond optimized for quantum technologies.

中文翻译：

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使用金刚石中的氮空位中心检测纳米级的氮空位氢中心

在金刚石中，氮缺陷如替代氮缺陷$（{\mathrm{氮}}_{\mathrm{s}}）$或者氮-空位-氢复合物（NVH）的数量比氮-空位（NV）缺陷多至少一个数量级，从而形成致密的旋转浴。虽然中立${\mathrm{氮}}_{\mathrm{s}}$对NV自旋态的相干性有影响，NVH的原子结构让人想起用氢原子装饰的NV中心。因此，NVH 中心的形成可能会与 NV 中心竞争，从而可能降低采用氢等离子体辅助化学气相沉积 (CVD) 生长的金刚石中的 N 到 NV 的转换效率。因此，监测和控制旋转浴对于生产和了解用于量子应用的高 NV 浓度的工程金刚石材料至关重要。虽然并入${\mathrm{氮}}_{\mathrm{s}}$多年来，人们一直在纳米和介观尺度上研究金刚石中的化学性质，但有关 CVD 参数和晶体取向对 NVH 形成的影响的研究仅限于块状 N 掺杂金刚石，为电子顺磁共振和光学提供足够高的自旋数。吸收光谱技术。在这里，我们研究了氮含量为的亚微米厚 (100) 金刚石层$（13.8\pm 1.6）\mathrm{百万分之一}$和$（16.7\pm 3.6）\mathrm{百万分之一}$，并利用层中的 NV 中心作为局部纳米传感器，我们演示了${}^{}{\mathrm{NVH}}^{-}$使用双电子-电子共振（DEER）中心。确定${}^{}{\mathrm{NVH}}^{-}$密度，我们定量地拟合了超精细结构${}^{}{\mathrm{NVH}}^{-}$并用通常用于测定的DEER方法确认结果${}^{}{{\mathrm{氮}}_{\mathrm{s}}}^0$密度。通过我们的实验，我们获得了纳米级的旋转浴组合物，并使用薄金刚石层而不是资源和时间密集型的块状晶体，在 CVD 配方优化中实现了快速反馈循环。此外，量化${}^{}{\mathrm{NVH}}^{-}$对于了解空位动态以及将氢掺入针对量子技术优化的 CVD 金刚石中起着非常重要的作用。