Adsorption of V-group elements and oxygen on Si(0 0 1)2×1 surface

The influence of atomic oxygen on the Si(0 0 1)/As, Si(0 0 1)/Sb and Si(0 0 1)/Bi surfaces has been investigated by MNDO-PM3 semiempirical method. The potential energy surfaces for atomic oxygen adsorbed on ideal Si(0 0 1)/M-(1 ML) surface (where M=As, Sb and Bi) have been calculated. Three equilibrium binding sites have been found for atomic oxygen adsorption with the formation of M–O–M, M–O–Si and Si–O–Si bridge structures (where M=As, Sb and Bi). The formation of Si–O–Si bridge structures has been found to be the most energetically favourable. Trench-like defects formed by the missing rows of the metal dimer on the Si(0 0 1)/As, Si(0 0 1)/Sb and Si(0 0 1)/Bi surfaces have been simulated. It has been found that the incorporation of the atom of oxygen in the silicon residual dimer with the Si–O–Si bridge structure formation is the most energetically favourable. The processes of the dissociation of the oxygen molecule have been considered on trench-like defect. The activation and non-activation dissociation channels of molecular oxygen on trench-like defects have been revealed. The molecular oxygen dissociation barrier decreases with the increase of the atomic number of V-group metals adsorbed on Si(0 0 1) surface.