Effect of oxygen and fluorine absorption on the electronic structure of the InSb(111) surface

The projector augmented-wave method was used to study the energetics of oxygen and fluorine bonding on the InSb(111) surface depending on its termination. It is shown that the fluorine adsorption on the In-terminated surface depending on its concentration leads to a partial or complete removal of surface states induced by oxygen adsorption from the forbidden gap. Penetration of both adsorbates into subsurface layers results in breaking of In–Sb bonds and the formation of chemical bonds of fluorine and oxygen with subsurface atoms of the substrate. It is the initial stage of the formation of a fluorine-containing anode oxide layer. In the case of the InSb(111) surface terminated by antimony, oxygen adsorption contributes to a decrease in the density of surface states in the forbidden gap. The general trends in the changes of the electronic structure of the (111) surface during the fluorine and oxygen coadsorption are discussed in a set of III–V semiconductors.