Energy levels and charge state control of the carbon antisite-vacancy defect in 4H-SiC

The carbon antisite-vacancy pair (CSiVC) in silicon carbide (SiC) has recently emerged as a promising defect for applications in quantum communication. In the positive charge state, CSiVC+ can be engineered to produce ultrabright single photon sources in the red spectral region, while in the neutral charge state, it has been predicted to emit light at telecom wavelengths and to have spin properties suitable for a quantum bit. In this electron paramagnetic resonance study using ultrapure compensated isotope-enriched 4H-(SiC)-Si-28, we determine the (+|0) level of CSiVC and show that the positive and neutral charge states of the defect can be optically controlled.Funding Agencies|Swedish Research Council [VR 2016-04068, VR 2016-05362]; Swedish Energy Agency [43611-1]; Knut and Alice Wallenberg Foundation [KAW 2018.0071]; Japan Society for Promotion of Science KAKENHI [17H01056, 18H03770]