Photoinduced EPR and ENDOR studies of the divacancies and nitrogen-vacancy defects in silicon carbide^†

Defects (color centers) in wide-gap semiconductors are considered as the basis for the realization of highly sensitive sensors, single-photon sources, and for the implementation of quantum technologies. Silicon carbide (SiC) crystal can serve as a reliable solid-state matrix for the range of high-spin (electron spin S = 1) color centers to become an alternative to the diamond with the widely-known nitrogen-vacancy (NV⁻) centers. This paper reviews the electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) studies of the divacancies (VV) and negatively charged NV⁻ centers in different SiC polytypes. The main spin Hamiltonian components of non-equivalent spin defects in SiC are presented depending on their structural features (positions) and local environment: the zero-field splitting (D ≈ 1.3 GHz), hyperfine (A ≈ 1.1 MHz) and quadrupole (P ≈ 1.8 MHz) interaction values. The luminescence spectrum of the color center in SiC (λ = 1.1 − 1.25 µm) in near-IR range is favorable for fiber-optic channels (O-band) and biological objects study, which brings these defects to a higher level of practical application.