Ab initio simulation of p-type silicon crystals

Porous silicon (p−Si)(p−Si) morphology depends on several parameters of the crystalline silicon substrate such as doping type and carriers concentration. Experimental results on (p−Si)(p−Si) show that although in the porous samples carriers are greatly reduced, boron atoms remain in the bulk. The study of p-type silicon crystals substrates by means of ab initio   computational simulations will help to understand how boron atoms behave during the electrochemical reaction of porous silicon (p−Si)(p−Si) fabrication. Here we studied the properties of p-types crystalline silicon models analyzed using the ABINIT code. We constructed 4 silicon crystal models with a maximum of 216 atoms by simulation cell. The optimized geometries and some electronic properties were obtained. We observed that around the boron impurity the crystal lattice is deformed because of the bonding length Si−BSi−B. The total energy increases with the number of boron atoms by simulation cell. The relative electronic densities indicated that the charge contributions to the dangling bond, produced by the presence of the boron impurity, are mainly distributed around its first silicon neighbors.

► This work study the role of boron atoms on the porous silicon fabrication.
► Our p-silicon models reproduce the experimental resistivity of the silicon wafers.
► We obtained the boron effect on the p-type silicon lattice.
► We obtained the electronic behavior around the boron impurities.
► We studied the topological and electronic effect of the p-type silicon doping level.