Phase diagram, chemical bonds, and gap bowing of cubic InxAl1-xN alloys:: Ab initio calculations

Thermodynamic, structural, and electronic properties of cubic InxAl1-xN alloys are studied by combining first-principles total energy calculations and the generalized quasichemical approach. Results for bond-lengths, second-nearest-neighbors distances, and bond angles in the alloy are presented. The calculated phase diagram of the alloy shows a broad and asymmetric miscibility gap. The gap fluctuations in the alloy allow for the definition of a minimum gap and an average gap with different bowing parameters, that can provide an explanation for the discrepancies found in the experimental values for the bowing parameter. It is also found that lattice matched In0.2Al0.8N with GaN is suitable to form a barrier material for electronic and optoelectronic nitride based devices. (C) 2002 American Institute of Physics.