States of silicon nanoclusters containing carbon impurities

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The structural and electronic states of defective complexes in the Si29 cluster with the participation of carbon and hydrogen atoms were determined by the method of non-conventional strong binding (MNSB) in combination with the method of molecular dynamics. It is shown that carbon atoms in silicon clusters form a bridge bond with two silicon atoms and localized in a hexagonal position at the center of the cell, forming a defect of the Si29 : Ci type. The introduction of hydrogen into a silicon cluster results in the formation of a defective Ci-H-Si complex and a decrease of binding energy of the Si29 : Ci defect. Based on the calculations, it was found that presence of leads to carbon gives shallow levels in the band gap of nano-silicon, and the defective carbon-hydrogen complex in a hydrogenated cluster, depending on the charge state of the defective complex. Moreover this exhibits both deep and shallow levels. Keywords: MD and MNSB methods, silicon nano-clusters, hydrogenated cluster, structural defects, ab initio methods, carbon and hydrogen atoms, spatial structure, shallow and deep levels.