First principles calculations in silicon: Structural and electronic properties of point defect

Using first-principles calculations, the structural and electronic properties of point defected silicon systems were systematically studied. Based on this, the mobility of pure and defected silicon were calculated by a combination method of first-principles and Boltzmann transport theory. The results indicate that there are some defect bands appear in the band gap of defected Si, and the defect bands increase with the number of defects, resulting in the changes of the density of states (DOS) around Fermi level. The electron mobility increases with the number of defects. However, the hole mobility decreases with the number of defects. In addition, the influence of temperature to mobility was calculated. The results show that both electron and hole mobility decreases with temperature.