Calculation of Defects in Silicon by a New Tight-Binding Model

The structural and electronic properties of monovacancy, divacancy defects within crystalline silicon have been investigated systematically using a new tight-binding model with a 216-atom supercell. The formation energies and energy levels of all the defect configurations are carefully calculated. The results show that atoms nearer to the defects naturally contribute to gap states more, and are comparable with the experimental values.