Quantum chemical study of the Co-adsorption of NH3 and MMAl on ideal AlN(0 0 0 1)-Al surfaces

Abstract

By employing the density functional theory, the co-adsorption of surface reaction precursors NH3 and MMAl on ideal AlN(0 0 0 1)-Al surfaces was investigated during the growth of AlN MOVPE. The adsorption mechanism of the particles on the surface was determined by analyzing the adsorption energy, molecular interaction energy, population of chemical bonds, and partial density of states. The study found that when comparing the co-adsorption reactions of NH3 and MMAl at different adsorption positions with an individual adsorption of particles on the surface: ① the co-adsorption and single adsorption of NH3 and MMA on the surface concluded similarly, that is, the stable adsorption of NH3 was at the Top site; while the stable adsorption of MMAl was at the T4 and H3 sites, but the co-adsorption structure was more stable. ② A chemical reaction took place between NH3, MMAl and the surface atoms with the reaction equation: 3Al(s) + NH3(ads) + AlCH3(ads) → Al(s)–NH2(ads)-Al(ads)-2Al(s) + CH4. Here, Al in MMAl was adsorbed on the Br site, and the N in NH3 was adsorbed on the Top site.