First-Principles Study on Native Defect Complexes in InN

We present first-principles calculations of the formation energy of different native defects and their complexes in wurtzite InN using density-functional theory and the pseudopotential plane-wave method. Our calculations are aimed in the three cases: N/In =1, N/In>1 (N-rich), and N/In<1 (In-rich). Our results indicate that the antisite defect has the lowest formation energy under N/In =1. The formation energy of nitrogen interstitial (nitrogen vacancy) defect is significantly low under the N-rich (In-rich) condition. Thus the antisite defect is an important defect if N/In=1,and the nitrogen interstitial (nitrogen vacancy) defect is a vital defect under the N-rich (In-rich) condition. The atomic site relaxation around the nitrogen interstitial and vacancy is investigated. Our calculations show that the nitrogen vacancy cannot be observed although it is one of the most important defects in InN. Our results are confirmed by experiments.