High-quality, deep formation and identification of oxygen-vacancy defects in silicon carbide

Abstract

Optically addressable paramagnetic defects in silicon carbide (SiC) are attractive for scalable quantum technologies such as quantum sensing. PL5, PL6, and PL7 are promising defects for their high brightness and spin-readout contrast. Although generation by oxygen implantation has been reported very recently, nonuniform spin and optical properties and the limited generation depth of implanted defects hinder both high-sensitivity sensing and conclusive microscopic identification. Here we engineer high-quality defects by decoupling oxygen incorporation and defect formation, realizing highly homogeneous spin-resonance frequencies as well as narrow optical linewidths and long T2* coherence time. Further, we demonstrate defect formation beyond the ion range utilizing oxygen diffusion, exceptional among impurities in SiC. We further provide hyperfine-interaction statistics of 17O and host nuclei across many PL6 defects, making the oxygen-vacancy origin conclusive. Together, the microscopic identification and the demonstrated formation route establish a foundation for developing the oxygen-vacancy spin defect into a versatile quantum platform.

Optically addressable PL5, PL6, and PL7 defects in silicon carbide are candidates for quantum sensing, but oxygen-implantation-based preparation has produced nonuniform spin and optical properties and restricted formation depths. This paper addresses whether oxygen incorporation and defect creation can be separated to improve defect quality and extend the accessible depth, while establishing the defects’ microscopic composition. The reported preparation route decouples oxygen incorporation from subsequent defect formation. The abstract reports highly homogeneous spin-resonance frequencies, narrow optical linewidths, and long inhomogeneous spin-coherence times, $T_2^*$. It also reports defect formation beyond the implanted-ion range through oxygen diffusion in SiC. For microscopic identification, the study collects hyperfine-interaction statistics involving $^{17}\mathrm{O}$ and host nuclei across many PL6 defects. These measurements are presented as conclusive evidence for an oxygen–vacancy origin of PL6. The available abstract gives no numerical linewidths, coherence times, resonance-frequency spreads, formation depths, sample counts, or defect-generation yields, so the magnitude of the improvements and their reproducibility cannot be assessed here. It also does not specify the preparation conditions or how hyperfine statistics distinguish competing microscopic structures. Although PL5, PL6, and PL7 motivate the work, the stated microscopic-identification evidence concerns PL6 specifically. No additional limitations are stated in the abstract; the full text was unavailable.