Electrical Stark Tuning and In Situ Field Sensing of V₂ Silicon Vacancies in a 4H-SiC a-Plane Lateral pin-Diode

Silicon carbide has emerged as a highly promising platform for scalable quantum technologies, with the silicon vacancy serving as a robust spin qubit and quantum sensor. However, conventional c-plane 4H-SiC restricts the experimental scheme and resonant optical excitation to the sample's geometry. The usage of a-plane substrates enables more versatile resonant optical access to the color center through the wafer surface. Here, we demonstrate the electrical control and optical addressability of V₂ (cubic lattice site) silicon vacancies within the intrinsic region of lateral pin-diodes fabricated on a-plane 4H-SiC wafers using a scalable complementary metal-oxide-semiconductor (CMOS) process. Despite extensive semiconductor processing, the integrated color centers exhibit good optical quality, evidenced by narrow optical transition linewidths below 80 MHz at zero bias. These embedded quantum sensors are utilized for in situ measurement of local electric fields at cryogenic temperatures via the Stark effect. Comparisons with macroscopic technology computer-aided design simulations reveal the value of these integrated quantum sensors to help understand cryogenic device behavior, for example in predicting highly localized field crowding. Furthermore, to address the spectral indistinguishability required for quantum networks, we precisely tune the zero-phonon line (ZPL) of individual emitters via the reverse-bias Stark effect. This successfully compensates for the spectral variations of distinct emitters. Following the relaxation of transient charge fluctuations, the Stark-tuned emitters exhibit spectral stability over measurement periods exceeding four hours. Our results establish a-plane 4H-SiC as a robust platform for future interference experiments and quantum photonic integrated circuits.