Band gap engineering in amorphous AlxGa1−xN: Experiment and ab initio calculations

摘要: Amorphous alloys of aluminum nitride and gallium deposited at 100 K compositions ranging from pure AlN to GaN with optical band gaps which vary linearly composition 3.27 eV (a-GaN) 5.95 (a-AlN) have been synthesized. Ab initio molecular dynamics calculations for these reproduce the gap versus data give specific information on electronic localization tail states. There are no midgap states in amorphous AlxGa1−xN alloys. The calculated models mixed four-fold three-fold coordination wrong (homopolar nuclear) bonds, demonstrating strong ionicity It has found that valence mostly localized coordinated N sites while conduction Ga or Al sites.