Effect of Native Defects on Optical Properties of InxGa1-xNAlloys

The energy position of the optical absorption edge and the free carrier populations in In{sub x}Ga{sub 1-x}N ternary alloys can be controlled using high energy {sup 4}He{sup +} irradiation. The blue shift of the absorption edge after irradiation in In-rich material (x > 0.34) is attributed to the band-filling effect (Burstein-Moss shift) due to the native donors introduced by the irradiation. In Ga-rich material, optical absorption measurements show that the irradiation-introduced native defects are inside the bandgap, where they are incorporated as acceptors. The observed irradiation-produced changes in the optical absorption edge and the carrier populations in In{sub x}Ga{sub 1-x}N are in excellent agreement with the predictions of the amphoteric defect model