Site-Dependent Properties of Quantum Emitters in Nanostructured Silicon Carbide

Deep defects in silicon carbide (SiC) possess atom-like electronic, spin and\noptical properties, making them ideal for quantum-computing and -sensing\napplications. In these applications, deep defects are often placed within\nfabricated nanostructures that modify defect properties due to surface and\nquantum confinement effects. Thus far, theoretical studies exploring deep\ndefects in SiC have ignored these effects. Using density functional theory,\nthis work demonstrates site-dependence of properties of bright,\nnegatively-charged silicon monovacancies within a SiC nanowire. It is shown\nthat the optical properties of defects depend strongly on the hybridization of\nthe defect states with the surface states and on the structural changes allowed\nby proximity to the surfaces. Additionally, the analysis of the first\nprinciples results indicates that the charge-state conversion and/or migration\nto thermodynamically-favorable undercoordinated surface sites can deteriorate\ndeep-defect properties. These results illustrate the importance of considering\nhow finite-size effects tune defect properties, and of creating mitigating\nprotocols to ensure a defect's charge-state stability within nanostructured\nhosts.\n