Low temperature ODMR of silicon vacancies in 4H-SiC nanopillar arrays for wide-field magnetic imaging

With the rapid development of quantum devices and materials, characterization of the microscopic fields influencing them is of significant interest. Wide-field magnetic imaging, currently with nitrogen vacancy (NV) ensembles in diamond, has begun to play an important role in this area. However, the cost of diamond films, difficulty of obtaining thin NV layers with low inhomogeneity, and small sample sizes compel researchers to look for alternative spin-defect platforms. The V2 silicon vacancy in 4H-SiC is one such promising system, but the optically-detected magnetic resonance (ODMR) contrast is typically only 0.5%, limiting sensitivity. We have recently demonstrated ~50% ODMR contrast for V2 ensembles in 4H-SiC through resonant optical excitation at low temperatures. We have also fabricated nanopillar arrays on a ~1 μm thick epilayer of 4H-SiC to facilitate efficient resonant excitation, enhancement of photon collection, and high spatial resolution. We will discuss low-temperature, resonant ODMR in these structures and efforts to implement wide-field imaging with them. In addition, we observe large changes in photoluminescence (PL) due to magnetic fields orthogonal to the c-axis that have potential for RF-free magnetic imaging.