Electronic state calculations of Si quantum dots: Oxidation effects

Electronic states for the configuration of a Si dihydride backbonded to oxygen on the H-covered surface of spherical ${\mathrm{Si}}_{35}{\mathrm{H}}_{36}$ quantum dots (QDs) are calculated self-consistently using the extended Hückel-type nonorthogonal tight-binding method. The proposed backbond oxidation accounts for oxidation-induced redshifts in luminescence-peak energy observed in porous Si. It is found that optical transitions between the band edges in the Si QD backbonded to oxygen are dipole allowed as in the H-covered case. A comparison is made with a calculation for the double-bonded oxygen configuration.