Theoretical investiagation on optical characteristics of functionalised silicon quantum dots

Functionalization of Si surfaces at the nanoclusters size is a crucial step that can give a great opportunity to use them in an enormous range of applications, including optical sensing, biological fluorescence imaging and optoelectronic devices. Using density functional theory calculations, light-absorption and luminescence processes are modelled at the quantum mechanical level. Optimized geometries and electronic structures of hydrogenated silicon quantum dots of ~1 nm diameter attached to a diversity of chemical functional groups. In-depth characterization of their electronic structure and optical absorption shows that the impact upon the optical properties of the quantum dot depends strongly upon the form of the functional group: in some impartant cases electron states are introduced into the band-gap leading to non-radiative recombination.