GaN and InGaN(11(2)under-bar2 surfaces: Group-III adlayers and indium incorporation

First-principles calculations for clean and In-rich GaN(11 (2) under bar2) surfaces indicate that indium will, for the same indium chemical potential, incorporate in higher concentrations on the (11 (2) under bar2) surface than on the (10 (2) under bar0) surface. Because In atoms are larger than Ga atoms, there is a strain-induced repulsive interaction between incorporated In atoms on the surface. This interaction is weaker on the (11 (2) under bar2) surface in comparison to the (10 (1) under bar0) surface. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3240401]