Ag adsorption on Cd-terminated CdS (0 0 0 1) and S-terminated CdS (0 0 0 1̄) surfaces: First-principles investigations

First-principles calculations are performed to study the adsorption of Ag at Cd-terminated CdS (0 0 0 1) and S-terminated CdS (0 0 0 1̄) surfaces as a function of Ag coverage. Our results reveal that Ag adsorption at Cd-terminated (0 0 0 1) has a large binging energy than at S-terminated (0 0 0 1̄) surface. For Ag adsorption at Cd-terminated (0 0 0 1) surface, T4 structure is more favorable and the Ag–Cd bond posses an ionic-like character. While for Ag adsorption at S-terminated (0 0 0 1̄) surface, the H3 structure is most stable and the bonding between Ag–S is covalent. It is found that the magnitude and the sign of surface dipole moment are partly determined by the difference between the electronegativities of Ag and the host atom bonding with Ag. The adsorption energy changes as a function of Ag coverage. In addition, related properties of Ag cluster adsorption at Cd-terminated (0 0 0 1) surface are also discussed.