Surface passivant effects on electronic states of the band edge in Si-nanocrystals

We studied the effect of the surface passivants fluorine (F), chlorine (Cl), oxygen (O) and oxygen-related OH on the energy band edge states of clusters with the same Si29 and Si47 core by means of the atomic cluster model and density functional theory (DFT). The results confirm that the electronic states of the band edge in clusters are sensitive to these passivants, and the passivant O that may form double bonded structure affects the band edge states most strongly. The results may be helpful for understanding and controlling the electrical and optical properties of nanocrystalline silicon.