A theoretical analysis of the molecular and dissociative adsorption of H2O on GaAs(110)

The interaction of O, H, OH and H2O with a GaAs(110) surface is analyzed using a self-consistent LCAO approach supplemented with a local density approximation. Chemisorption energies for the different species are calculated and the possibility of either molecular or dissociative adsorption for water is discussed. Our results show that water adsorbs molecularly on GaAs(110), with O bonded to the Ga atoms; the adsorption energy on As is smaller but the initial semiconductor surface relaxation might favour water adsorption on the anion.