Spin coherence as a function of depth for high-density ensembles of silicon vacancies in proton-irradiated 4H–SiC

Defects in wide-band-gap 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 optically controlled spin qubits 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. These results will inform further routes toward fabrication of scalable silicon carbide devices and studies of spin interactions in high-density ensembles of defects. •High-density ensemble of SiC vacancies created via proton irradiation.•Spin coherence measured as a function of depth in sample.•Coherence time drops drastically as proton stopping layer approached.