Density Functional Theory Calculations of Ultrathin Epitaxial Au Overlayers on CdS(0001) and CdS(000(1)over-bar)

We apply a first-principle method based oil plane-wave density functional theory, with the generalized gradient approximation and pseudopotentials, to study the energetics and electronic properties of thin Au overlayers on CdS(0001) and CdS(000 (1) over bar) surfaces. Several viable Structures are optimized by total-energy-and-force minimization. Computed data for the relative formation energies, hand structures, densities of states, electron wave functions, work functions, and Schottky barrier heights are presented and discussed, also in relation to Au/CdSe systems. Our results reveal that thin epitaxial Au bilayers may be formed oil US surfaces within the allowed range of Cd chemical potential and in Au-rich conditions, with significant orbital mixing between S and Au Occurring at the interface. We analyze similarities and differences between Au/CdS and Au/CdSe systems: the behavior is overall qualitatively the same, with numerical differences in the computed quantities.