NDnano Faculty Networking Lunch
This is the monthly networking meeting for faculty and staff affiliated with NDnano. Newcomers are welcome! For more information on affiliating with the Center, please contact Heidi Deethardt at firstname.lastname@example.org.
David Beke, Postdoctoral Research Associate, Department of Physics and Astronomy
Size-Dependent Properties of Silicon Carbide Nanostructures and How to Create Room-Temperature Defect Qubits Inside Them
Silicon carbide (SiC) is a stable, chemically inert wide band gap semiconductor. The historical application of SiC includes abrasives, high-energy devices, and replacing silicon wafers in integrated circuits in harsh environments. Beyond the classical application, this material found its place in quantum technology, which harvests the stability, the long coherence time, and the emission wavelength in the telecommunication window of the optically active point defect, color centers, or quantum bits in SiC, such as the negatively charged silicon-vacancy that has zero-phonon lines between 900-1000 nm, or the neutral divacancy that emits around 1300 nm. These vacancies have high spin ground states with nonzero zero-field splitting, allowing optical manipulation of the spin states for quantum information processing. The nanostructured SiC is also a promising candidate for bioimaging, targeted drug delivery, nanosensing, optoelectronic, and heterogeneous photocatalysis.
Such a wide variety of auspicious applications is seeking the need for a complex understanding of the SiC nanosystems. Here we demonstrate the size- and surface-dependent physical properties of SiC nanoparticles below 10 nm, close to the exciton Bohr radius, and show how the size affects the optical properties and photocatalytic activity exactly when energy levels transform from continuous to discrete states and interactions with biological media.
While many properties of SiC NPs are affected by their size, the optical properties can be further tuned with color centers. The fabrication of NPs below 10 nm with a high yield of NPs containing a qubit inside is still challenging for many materials. We show a whole chemical method that excludes any high-energy interaction to synthesize 4 nm divacancy containing NPs with high contrast room temperature optically detected magnetic resonance.