Dynamic reactions of defects in ion-implanted 4H-SiC upon high temperature annealing

Single-photon emitters based on intrinsic defects in silicon carbide (SiC) are promising as solid-state qubits for the quantum information storage, whereas defect engineering in a controllable manner still remains challenging. Herein, the thermally-driven defect dynamic reaction in the ion implanted 4H-SiC has been exploited through the optical emission spectra of defects. For the heavy-ion (Si or Ar) implanted samples with abundant Frenkel pairs, the silicon vacancies (V-Si) are energetically converted into the carbon antisite-vacancy pair (C-Si-V-C) upon annealing till 1300 degrees C for 30 min, accompanied with the gradual lattice recovery and local strain relaxation. The further temperature elevation dissociates the metastable C-Si-V-C into carbon antisite (C-Si) and carbon vacancy (V-C), as supported by the consequent quenching of the (C-Si-V-C)-related emission at 700 nm. Thus, the whole defect reaction is probed as the vacancy interconversion from V-Si to V-C with the byproduct of stacking faults. In contrast, the intermediate C-Si-V-C complexes are not energetically favorable during the annealing of the H-implanted sample, which results from the negligible generation of Frenkel pairs, as supported by the x-ray diffraction patterns and Raman scattering analysis. These findings provide guidance for defect engineering in SiC toward the creation of reliable single photon emitters.