Theoretical analysis of semiconductor surface passivation by adsorption of alkaline-earth metals and chalcogens

► Ab initio theoretical studies of the electronic structure of chemisored semiconductor surfaces. ► Understanding of semiconductor passivation at atomic level. ► Detailed analysis of structural models for Ca/Si(001), Ca/Si(111), and S/GaAs(001) surfaces for sub-monolayer elemental coverages. We begin with the concept of semiconductor surface passivation by adsorption of sub-monolayer atomic coverages. We then present a theoretical analysis of structural reconstruction and passivating behaviour of semiconductor surfaces upon sub-monolayer adsorption of alkaline-earth metals (group II atoms) and chalcogens (group VI atoms). Specific results are presented from first-principles calculations for Ca adsorption on Si(001) and Si(111), and S adsorption on GaAs(001). The role of chemical species of adsorbate and surface atoms in achieving different degrees of passivation is highlighted.