Preparation and transformation of color centers in 4H-SiC by electron irradiation and subsequent annealing

Achieving color center preparation with deterministic type and controllable concentration is crucial for quantum applications, such as quantum sensing and quantum communication. Numerous defects can be introduced in 4H-silicon carbide (4H-SiC), and they are capable of undergoing transformations under specific circumstances. Exploring defects’ transformation conditions is essential for optimizing the color center preparation parameters. Herein, the preparation and transformation of color centers in 4H-SiC by electron irradiation and subsequent annealing treatment are investigated. Firstly, silicon vacancy was prepared using electron irradiation (2 MeV and 10 MeV, 10¹⁴–10¹⁷ e cm⁻²). Subsequently, a phenomenon of silicon vacancy conversion to carbon antisite vacancy pairs (CAV) was discovered in the 2 MeV 10¹⁶ e cm⁻² sample. Then, a comparison was made between the defect transformation caused by irradiation and annealing, and it was found that the former was not as thorough as the latter, accompanied by two unknown intermediate states, but they could ultimately be eliminated by annealing. Finally, the preparation conditions for silicon vacancy and CAV were optimized, with 2 MeV irradiation being effective for preparing CAV, whereas 10 MeV irradiation yields a higher quantity of silicon vacancy. Our findings serve as a crucial step in the preparation of color centers and lay the foundation for the application of color centers in quantum field.