Finite-size and Surface effects: Deep Defects in Nanostructured SiC

Spin-active deep defects in wide-bandgap semiconductors like silicon carbide (SiC) are being studied for application in quantum technologies, such as quantum computing, and nanoscale field sensing. Often these applications involve nanostructuring of the host semiconductor. In a nanostructure, the electronical and optical properties are expected to be affected by surface and quantum confinement effects. In our work, we investigate these finite size effects by studying the properties of silicon vacancies with different charge states in 2H-SiC (wurtzite) nanowires. Defect properties like formation energy, spin, and spin polarization energies are shown to be site-dependent in the nanostructured host. Our results indicate that a surface acts as a sink for the defects, and the migration of defects towards the surface may lead to the loss of the signal from a defect placed in a nanostructured host.