Classical and quantum simulations of In and Al incorporation in GaN

A theoretical investigation of the energetics of In and Al incorporation in GaN is carried out. By considering pairs and triplets of substitutional at oms in various configurations, we have determined whether there is an energ etic driving force for ordering or clustering to take place. Using a quantu m approach it is shown that the binding energy is negative for pairs of ind ium substitutionals in nearest neighbour configurations and positive for no n nearest neighbour configurations. This implies a preference for indium to order within the GaN lattice. Aluminium pairs, in contrast, have a near ze ro binding energy for all configurations which implies that the incorporati on of aluminium should be random.