CHARGE-DENSITY TRANSFER OF H-ADSORPTION ON THE SI(111) (1X1) SURFACE

The charge-density transfers from ab initio quantum mechanical calcula tions for the adsorption of hydrogen atoms on the Si(111) (1 x 1) surf ace are presented. In the initial stages of the adsorption, the intera ction occurs between the hydrogen atom and the surface dangling bond o r between the hydrogen atom and the hydrogen overlayer. The interactio n has the same characteristics as the initial stages of the hydrogen m olecule formation. For the adsorbed systems, the charge-density transf ers exhibit strong ionicity with the adsorbed hydrogen atoms being the more electronegative ones. The hydrogen atoms are negatively charged beneath the Si(111) (1 x 1) surface. This property is retained for the hydrogen atoms in the silicon bulk, no matter whether the system is n eutral or charged.