Research Projects

This proposal explores vacancies in silicon carbide (SiC) crystals as a compelling alternative to nitrogen-vacancy (NV⁻) centers in diamond for quantum sensing applications [1-6]. SiC offers several practical advantages: it benefits from mature fabrication techniques, supports wafer-scale growth at a relatively low cost [7-8], and avoids issues like P1 center formation that degrade the performance of diamond sensors. Unlike diamond, which mainly supports NV⁻ centers, SiC hosts a wide variety of quantum defects—including silicon vacancies (VSi), divacancies (VCVSi), and antisite defects [9-16]. SiC exists in more than 250 polytypes (e.g., 4H-SiC, 6H-SiC, 3C-SiC) [10]. This diversity opens new opportunities for defect engineering, enabling tailoring of quantum properties for targeted applications. SiC-based defects emit photoluminescence in the near- to mid-infrared range (850–1300 nm) [7,9,10], closer to telecommunication wavelengths than the 637 nm emission of NV⁻ centers [17]. This significantly reduces Rayleigh scattering—by a factor of ~3 at 850 nm and ~17.5 at 1250 nm—making SiC more suitable for remote sensing and quantum communication, such as in quantum repeater networks. While magnetic and pressure sensing using bulk SiC crystals has been demonstrated, systematic studies on shallow vacancies (depth less then 100 nm) remain limited. Yet shallow centers are critical for surface-proximal quantum sensing, as their spin and optical properties—such as ODMR contrast and spin relaxation rates—can vary significantly with depth. Notably, a 6% ODMR contrast at room temperature has recently been reported for a single shallow VSi center at ~30–40 nm depth [18], underscoring the untapped potential of SiC defects. In this proposal, we aim to: Systematically characterize vacancies with varying depths and concentrations. Model relaxation rates as a function of depth for VSi divacancies, and NV⁻ centers in SiC. Identify and optimize the most promising defect systems for quantum sensing [19] and communication. Demonstrate quantum sensing in practical scenarios, including artificial signals, magnetic field imaging, pressure and temperature mapping, and scalable sensor arrays for on-chip integration [19], So, the proposal's main objective is to establish SiC as a scalable, robust, and cost-effective platform for next-generation quantum sensors [19], overcome the limitations of diamond-based systems, and enable broader adoption across scientific and industrial domains.