Charge state instabilities have been a bottleneck for the implementation of solid-state spin systems and pose a major challenge to the development of spin-based quantum technologies. Here we investigate the stabilization of negatively charged nitrogen-vacancy (NV⁻) centers in phosphorus-doped diamond at liquid helium temperatures. Photoionization of phosphorous donors in conjunction with charge diffusion at the nanoscale enhances NV⁰ to NV⁻ conversion and stabilizes the NV⁻ charge state without the need for an additional repump laser. The phosphorus-assisted stabilization is explored and confirmed both with experiments and our theoretical model. Stable photoluminescence-excitation spectra are obtained for NV⁻ centers created during the growth. The fluorescence is continuously recorded under resonant excitation to real-time monitor the charge state and the ionization and recombination rates are extracted from time traces. We find a linear laser power dependence of the recombination rate as opposed to the conventional quadratic dependence, which is attributed to the photo-ionization of phosphorus atoms.

电荷态不稳定性一直是固态自旋系统实现的瓶颈，并对基于自旋的量子技术的发展构成重大挑战。在这里，我们研究了液氦温度下掺磷金刚石中带负电的氮空位（NV ^{- ）中心的稳定性。}磷供体的光电离与纳米级的电荷扩散相结合，增强了 NV ⁰到 NV ^{- 的}转换并稳定了 NV ^-电荷状态，而无需额外的再泵浦激光器。通过实验和理论模型对磷辅助稳定进行了探索和证实。生长过程中产生的NV ^-中心获得稳定的光致发光激发光谱。在共振激发下连续记录荧光，以实时监测电荷状态，并从时间轨迹中提取电离和重组率。我们发现复合率呈线性激光功率依赖性，而不是传统的二次依赖性，这归因于磷原子的光电离。