Stabilizing excited-state silicon nanoparticle by surface oxidation

Si-Si and Si-H bonds in small hydrogenated Si particles are known to readily dissociate upon photoexcitation, which hinders various optical applications of Si particles. The authors show that the Si core could be stabilized in the presence of double-bonded oxygen (SiO) on the surface, based on excited-state calculations of a series of oxidized Si particles from Si5 H10 O to Si199 H138 O using the density-functional tight-binding method. The authors revealed that the stabilization effect is due to localization of excited-state relaxation mainly in the SiO region, which becomes significant when the particle size decreases. The possibility of fabricating stable Si nanoparticles by introducing a small amount of oxygen on the surface and the stabilization effect have important implications in device fabrications.