Theoretical investigation of the decomposition mechanism of AlN(0001) surface under a hydrogen atmosphere

The activation energies for Al and N desorption from an AlN surface were calculated using the density functional theory (DFT) to obtain a detailed understanding of the decomposition process of AlN(0001) Al and N surfaces under a hydrogen atmosphere. It was found that Al atoms on the AlN(0001) Al surface desorbed as AlH and formed AlH3 by reacting with two H atoms on the surface just after desorption, whereas N atoms on the AlN(0001) N surface desorbed as NH3 molecules from the surface. The desorption energy of Al on the hydrogen terminated surface was more consistent with previous experimental value than that on an ideal surface. This result suggests that the initial surface structure of the AlN(0001) surface is terminated with hydrogen. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim