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

The charge-density transfers from ab initio quantum mechanical calculations for the adsorption of hydrogen atoms on the Si(111) (1 x 1) surface are presented. In the initial stages of the adsorption, the interaction occurs between the hydrogen atom and the surface dangling bond or between the hydrogen atom and the hydrogen overlayer. The interaction has the same characteristics as the initial stages of the hydrogen molecule formation. For the adsorbed systems, the charge-density transfers 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 neutral or charged.