Tight-binding study of the {113} planar interstitial defects in Si.

Abstract

The atomic and electronic structure of the {113} planar interstitial defects in Si has been examined by using the transferable semiempirical tight-binding method, based on the reconstructed atomic model. The present results quantitatively confirm our previous conclusion obtained by use of the Stillinger-Weber potential [Phys. Rev. B 46, 12 305 (1992)] regarding the energy and atomic structure. The features of the electronic structure resemble those of reconstructed 〈110〉 tilt boundaries in Si. There exist no electronic states inside the minimum band gap in accordance with the small bond distortions, although defect-localized states are generated, especially at the conduction-band edge. Large portions of such localized states exist at the eight-membered rings and neighboring five-membered rings. Effects of bond distortions, odd-membered rings, and hexagonal six-membered rings at the defects on the local electronic structure have been observed, which are essentially consistent with those found in calculations of grain boundaries in Si. Possible origins of the gap states associated with the {113} defects have been discussed.