Calculating electronic properties of the Si:SiO2 interface using density functional theory with periodical boundary condition

Si:SiO₂ core-shell nanoparticles are ideal for photovoltaic applications due to their stability and easily tunable optical properties. Investigations with ab initio methods have the potential to lead to a better understanding of the electronic properties of these materials. Using density functional theory, we calculated the density of states, absorption spectra, and partial charge densities of a model interface composed of a pure silicon portion sandwiched between SiO₂ layers with a formula of Si₂₆₄O₁₆₀. Quantum confinement was observed in the pure Si portion, indicating that SiO₂ serves as an insulating barrier to charge delocalization within the interface. This provides theoretical evidence that tuning the size of the nanoparticles and the thickness of the silicon oxide layer can affect the electronic properties.