The 90° partial dislocation in silicon: Geometry and electronic structure

The core structure of the reconstructed 90° partial dislocation in silicon is obtained by energy minimization with respect to the Lifson-Warshel valence force field using periodic boundary conditions. A low strain energy attests to the stability of the reconstructed geometry. The electronic structure is calculated using a local pseudo-potential approach in an improved peripheral orbital treatment. The silicon indirect gap is found to be completely clear of dislocation levels, in agreement with experiment. Stacking-fault levels are found in the gap near the valence band edge in agreement with specialized stacking-fault energy level calculations.