Ab Initio Studies of Al and Ga Adsorption on 4H-SiC{0001} Surfaces

Changes in the atomic and electronic structure of Si- and C-terminated 4H-SiC{0001} surfaces resulting from aluminium and gallium adsorption have been studied within density functional theory framework. Al and Ga coverages ranging from a submonolayer to one monolayer were considered. Our results show that Al binds more strongly to both surfaces than Ga. The binding is stronger to the C-terminated surface for both metals. The sites occupied by Al and Ga atoms at 1 monolayer are different and it is due to a different charge transfer from metal to the substrate.