Silicon carbide (SiC) is a very promising platform for quantum information processing, as it can host room temperature solid state defect quantum bits. These room temperature quantum bits are realized by paramagnetic silicon vacancy and divacancy defects in SiC that are typically introduced by irradiation techniques. However, irradiation techniques often introduce unwanted defects near the target quantum bit defects that can be detrimental for the operation of quantum bits. Here, we demonstrate that by adding aluminum precursor to the silicon and carbon sources, quantum bit defects are created in the synthesis of SiC without any post treatments. We optimized the synthesis parameters to maximize the paramagnetic defect concentrations—including already established defect quantum bits—monitored by electron spin resonance spectroscopy.

The synthesis of silicon carbide has been widely explored to tailor its material properties for specific needs, particularly particle size, polytype distribution, and defect density.

Silicon carbide is a promising material for optically and spin-active point defects relevant to quantum applications. Quantum-relevant color centers are commonly generated by irradiation or implantation, which require specialized infrastructure and may introduce collateral lattice damage. Here, we present a chemical approach in which the influence of synthesis temperature, high-energy ball milling, and aluminum addition on formation, polytype distribution, and defect formation in SiC is investigated. We found that it is possible to create quantum-relevant defects throughout the chemical synthesis, and the temperature and mechanical activation are the dominant parameters governing defect generation. Photoluminescence and electron paramagnetic resonance spectroscopy demonstrate that low synthesis temperatures (1050–1150 °C) in high-energy ball-milled samples yield silicon vacancy and divacancy-related color centers, evidenced by characteristic near-infrared PL emission and high-spin EPR signals with zero-field splitting values D ≈ 1.3 GHz and D ≈ 270 MHz, consistent with neutral divacancies and V_Si–C_Si complex centers, respectively. An additional EPR signal at D ≈ 650–780 MHz, not matched by any previously reported defect configuration in SiC, is tentatively assigned to a second-nearest-neighbor divacancy-like (V_Si–V_C) pair.

Silicon carbide is a promising material for optically and spin-active point defects relevant to quantum applications. Quantum-relevant color centers are commonly generated by irradiation or implantation, which require specialized infrastructure and may introduce collateral lattice damage. Here, we present a chemical approach in which the influence of synthesis temperature, high-energy ball milling, and aluminum addition on the formation, polytype distribution, and defect formation in SiC is investigated. We found that it is possible to create quantum-relevant defects throughout the chemical synthesis, and the temperature and mechanical activation are the dominant parameters governing defect generation. Photoluminescence and electron paramagnetic resonance spectroscopy demonstrate that low synthesis temperatures (1050–1150 °C) in highenergy ball-milled samples yield silicon vacancy and divacancy-related color centers, evidenced by characteristic near-infrared PL emission and high-spin EPR signals with zero-field splitting values D ≈ 1.3 GHz and D ≈ 270 MHz, consistent with neutral divacancies and VSi–CSi complex centers, respectively. An additional EPR signal at D ≈ 650–780 MHz, unmatched by any previously reported defect configuration in SiC, points to a novel, “as yet unidentified” defect center formed under these synthesis conditions.