Single V2 defect in 4H Silicon Carbide Schottky diode at low temperature

Solid-state platforms have been pushed towards quantum technologies for a while now. Over the recent decades, color centers have matured into a valuable resource for quantum sensing, quantum communication or quantum computation. However, hosted in solids they are subject to the fluctuating electron charge environment [1] which deteriorates their quantum properties. Eliminating charge fluctuations in the host material is key for the fundamental scalability of the platform, so nanoelectrical and photonic integration of quantum optical components is crucial for scalable solid-state quantum technologies.

Silicon carbide (SiC) is a mature and well-developed wide bandgap (3.26 eV) CMOS-compatible material system. Due to its unique combination of optical, semiconductor and material properties, it is an excellent host for quantum emitters and spin defects [2]. Further, it is already a really attractive material for the high-power electronic device industry, providing a lot of nano-fabrication and chip-processing knowledge.

Here, we study the behavior of single silicon vacancy (V2) color centers in a metal-semiconductor (Au/Ti/4H-SiC) epitaxial wafer device, operating in a conventional Schottky diode configuration. We explore the depletion of free carriers in the vicinity of the defect, as well as electrical tuning of the defect optical transition lines. Additionally, we investigate the charge-photon dynamics of the V2 center and find its dominating photon-ionization processes characteristic rate and wavelength dependence. Finally, we probe the spin coherence properties of the V2 system in the junction and demonstrate several key protocols for quantum network applications. Our work shows the first demonstration of low-temperature integration of a Schottky device with optical microstructures for quantum applications and paves the way towards fundamentally scalable and reproducible optical spin defect centers in solids. Our work will have numerous applications in the whole research community.

[1] L. Orphal-Kobin et al., Physical Review X 13, 011042 (2023).

[2] H. Ou, Light: Science and Applications 13, 219 (2024)