BOWING PARAMETERS FOR ZINCBLENDE AL1-XGAXN AND GA1-XINXN

First-principles calculations have been used to determine bowing parameters for disordered zinc-blende Al1-xGaxN and Ga1-xInxN. The direct transition at Γ is found to bow downward for both materials with parameters +0.53 and +1.02 eV, respectively, while the Γ-to-X transition bows upward for Al1-xGaxN (parameter -0.10 eV) and downward for Ga1-xInxN (parameter +0.38 eV). The similarity of the calculated bulk zinc-blende and wurtzite Γ-point transitions also allows estimates to be made of the energy gap versus composition for wurtzite alloys.© 1995 American Institute of Physics.