Site discrimination and size effect of B-doping in Si nanocrystals by second-neighbor atom consideration

The site discrimination and the size effect on the formation energy Ef of the B atoms in B-doped Si nanocrystals (SiNCs) were studied by introducing a new parameter, the adjusted coordination number (ACN), which includes second-nearest neighbor atoms. A series of Ef values were obtained by using the first-principle calculation. It was found that the B-doping sites in the SiNCs can be well discriminated by ACN, and the change trends of Ef with either size or site become clear if one uses ACN as a describer. When the site is given, Ef has a decreasing trend when the size increases. However, when considering the sites with the same coordination number in a given Si nanocrystal, their Ef values increase with increasing ACN. Moreover, it was observed that sites with ACN = 3.375 are the usually preferred B-doping sites in these SiNCs when they exist.The site discrimination and the size effect on the formation energy Ef of the B atoms in B-doped Si nanocrystals (SiNCs) were studied by introducing a new parameter, the adjusted coordination number (ACN), which includes second-nearest neighbor atoms. A series of Ef values were obtained by using the first-principle calculation. It was found that the B-doping sites in the SiNCs can be well discriminated by ACN, and the change trends of Ef with either size or site become clear if one uses ACN as a describer. When the site is given, Ef has a decreasing trend when the size increases. However, when considering the sites with the same coordination number in a given Si nanocrystal, their Ef values increase with increasing ACN. Moreover, it was observed that sites with ACN = 3.375 are the usually preferred B-doping sites in these SiNCs when they exist.