Early Stages of Halogen Adsorption on Cation-Rich InAs(001): Surface Etching Mechanism

Comparative theoretical study of halogens (F, Cl, I) adsorption on cation-rich ζ-InAs(001)-(4 × 2) surface was performed within the density functional theory. The energetically preferable positions for Cl and I are found on-top of In-dimerized atoms whereas F prefers to adsorb between adjacent In surface dimers. The interaction of the halogen atom with In-dimerized atoms leads to weakening of the chemical bonds between In–As surface atoms, which is the origin of the initial stage of surface etching. The larger bonds weakening was found for the more electronegative F that has a tendency to break the dimers in InAs(001) and to induce stationary etching. The trend in the bonding mechanism of halogen atoms on InAs(001) surface is found to be common for other III–V semiconductor surfaces in the cation-rich limit