Electronic structure of oxygen in silicon

Abstract

Electronic structure calculations of the negativelly charged oxygen substitutional impurity in silicon (Si:O-) have been carried out within the framework of the multiple scattering-Xα method. By using clusters of 17 atoms we found that the Si:O- system introduces two energy levels in the crystal band gap. One of them is non-degenerate and fully occupied. The other one is a three-fold degenerate level and is occupied by one electron in the negative charge state. The calculations indicate that the Jahn-Teller effect occurs for the system, and distortions were included for the oxygen impurity and the four nearest neighbour silicon atoms.