First-principles study on the local vibrational modes of nitrogen-oxygen defects in silicon

In this paper we investigate the interaction of nitrogen and oxygen by means of local density functional theory. While nitrogen-pair-oxygen defects (N2-Om) have been studied in detail previously, the existence and role of nitrogen-oxygen defects containing only one nitrogen atom (N-On) is still controversial. Motivated by recent infrared absorption measurements, where several new absorption lines were observed, we present first-principles studies on the ground state configuration, binding energy and local vibrational modes of NO and NO2. We suggest that the NO2 defect gives rise to the experimentally observed lines at 1002, 973 and 855cm-1.