  Defects in wide-bandgap semiconductors provide a pathway for applications in
quantum information and sensing in solid state materials. The silicon vacancy
in silicon carbide has recently emerged as a new candidate for optical control
of single spin qubit with significant material benefits over nitrogen vacancies
in diamond. In this work, we present a study of the coherence of silicon
vacancies generated via proton irradiation as a function of implantation depth.
We show clear evidence of dephasing interactions between the silicon vacancies
and the spin environment of the bulk crystal. This result will inform further
routes toward fabrication of scalable silicon carbide devices and studies of
spin interactions of in high-density ensembles of defects.
