Characterization of single shallow silicon-vacancy centers in 4H-SiC

Shallow negatively charged silicon-vacancy centers have applications in magnetic quantum sensing and other quantum applications. Vacancy centers near the surface (within 100 nm) have different spin relaxation rates and optical spin polarization, affecting the optically detected magnetic resonance (ODMR) signal. This makes it essential to characterize these centers. Here we present the relevant spin properties of such centers. ODMR with a contrast of up to 6 %, which is better than the state of the art, allowed us to determine the zero field splitting, which is relevant for most sensing applications. We also present intensity-correlation data to verify that the signal originates from a single center and to extract transition rates between different electronic states.