Vacancies and B doping in Si nanocrystals

We examine the effect of vacancies on the doping of Si nanocrystals with B atoms. The electronic structure problem is solved in real space using pseudopotentials constructed within density functional theory. In the absence of vacancies, we find that it is energetically favorable for B dopants to be placed at or near the nanocrystal surface. However, in the presence of a vacancy, the B dopant can be stabilized within the nanocrystal as the vacancy effectively relieves the dopant induced stress.