Precisely Located Si Vacancies in 4H-SiC Generated via Focused Li-ion Beam for Quantum Information Science Applications

Photo-stable and spin (S = 3/2) coherent silicon vacancies (V_Si) in the CMOS compatible semiconductor SiC are of interest for future applications in scalable quantum information and sensing. The ability to precisely create the desired density at the optimal location in a three-dimensional solid-state matrix with nanometer accuracy and excellent optical properties is indispensable for the above applications. Here we demonstrate the precise generation of single and ensemble emitter arrays in defect-free epitaxial 4H-SiC layer through Li-ions, implanted with an energy of 100 keV and doses ranging from 10¹²–10¹⁵ Li/cm² using a maskless focused ion beam technique (~25 nm diameter spot positioned with ~25 nm accuracy and having anion travel depth of ~400 nm). High-resolution photoluminescence (E⊥c) studies revealed the scalable and reproducible defect generation with a mean efficiency of ~17% and intensity (~8 kC/s), yield (~28%), statistical distribution, average number of single V_Si/spot, fluorescence saturation, and photostability of single emitters. Given the encouraging results, we will discuss utilizing this approach to implant single V_Si into the mode maximum of SiC photonic crystal cavities with Purcell enhancement of zero-phonon line and increased photon indistinguishability.