The CsCs and CsCsV Defects in Silicon: Density Functional Theory Calculations

Carbon-related defects in silicon (Si) are commonly introduced during crystal growth via the Czochralski method and processing. They can play an important role in affecting the physical properties of Si and its application in nanoelectronic devices. In this study, we use spin polarised density functional theory (DFT) to model the most stable structures of C-doped (C), CsCs and CsCsV in Si and their electronic structures. For completeness we also consider the CsV and CsVV which have been modelled with DFT in previous work. The results of this study reveal that the substitution of C requires an external energy of 0.44 eV. Formation of all clusters is endoergic. The energy to bind isolated defects to form clusters is negative in all cases meaning that there is a strong tendency for the aggregation of isolated defects to form clusters.