Localized formation of optically active spin defects in SiC using MeV proton microbeams generated by a glass capillary

Negatively charged silicon vacancies (VSi) in silicon carbide are optically active spin defects that have attracted considerable interest in quantum sensing and device-integrated applications. Precise control over the localized formation of these defects is essential for their applications. In this study, we demonstrate the controlled creation of VSi defects in a targeted area of 4H–SiC using 1.16 MeV hydrogen microbeams generated via a high-aspect-ratio glass capillary (acceleration voltage: 1.3 MV; outlet diameter: 2.7 μm). The defect density was successfully regulated with the well-stabilized microbeam. Compared to focused MeV ion microbeams that rely on multipole electromagnets, the experimental setup employing glass capillary microbeams is both straightforward and cost-effective. This technique is versatile, accommodating various ion species and beam energies ranging from keV to MeV, making it suitable for generating a wide range of solid-state spin defects, including VSi defects. Consequently, this method holds promise for advancing research on the controlled formation of quantum sensors. Furthermore, we show that the microbeam spot size and axial defect distribution can be visualized by analyzing the spatial distribution of photons emitted from the generated VSi defects. The formation of VSi defects is attributed to atomic displacement induced by nuclear energy deposition, suggesting potential applications of 4H–SiC as microbeam profile monitors.