Stability of nitrogen incorporated Al2O3 surfaces: Formation of AlN layers by oxygen desorption

► The incorporation of nitrogen on Al2O3 surfaces is theoretically investigated. ► The O atoms of Al2O3 surfaces can be replaced by N atoms under pregrowth conditions. ► The outermost O atoms tend to desorb from the surface. ► AlN layers are consequently formed on Al2O3 surfaces. ► The calculated N-incorporated structures agree with those in the experiments.