Fabrication of high-brightness silicon vacancy color-center ensembles in 4H-SiC via MeV particles

The silicon vacancy (VSi−) color centers in 4H-SiC are promising solid-state spin defects for quantum sensing applications, featuring long room-temperature coherence times, near-infrared photoluminescence, and an optically controllable spin–photon interface. However, it is essential to achieve high-brightness silicon vacancy color-center ensembles by different irradiations for efficient signal detection and high-fidelity quantum sensing. In this work, we conducted irradiation experiments of MeV electrons, protons, and laser-driven ions to investigate the influence of irradiation parameters on the fabrication of VSi− center ensembles, confirming the vital roles of crystal damage densities in the production yield of VSi− centers. Furthermore, the hot irradiation experiments reveal that irradiation at optimized temperatures can enhance the production yield of VSi− centers and break the inherent limitation of radiation-induced crystal damage, achieving higher-brightness ensembles. 1 MeV proton irradiation with 1013 cm−2 at 200 °C could achieve a 2–3 times stronger photoluminescence intensity enhancement than that at room-temperature irradiation. We established a controllable fabrication methodology for engineering the brightness of color-center ensembles through precise tuning of irradiation conditions, which paves the foundation for fabricating high-quality VSi− color-center ensembles and other color-center systems in wide-bandgap semiconductor materials.