Structural and electronic properties of the adsorption of oxygen on ALN (10̄10) and (11̄20) surfaces: A first-principles study

By using first-principles calculation methods, the structural and electronic properties of the adsorption of oxygen on wurtzite AlN (10̄10) and (112-0) surfaces are investigated. Atomic adsorption is supposed to be the main adsorption morphology for both surfaces because it is more stable in energy than molecular adsorption and O₂ can dissociate easily during access to the surfaces. The stable adsorption sites on the two surfaces are not unique but the diffusions of O adatoms between them are limited by high energy barriers. The spin polarization of the triplet O and O₂ is relieved after adsorption. Detailed analysis of the electronic band structures shows that the adsorbates tend to drive away the original surface states from the bulk band gap but introduce into oxygen related states.