Ab–Initio large unit cell calculations of the electronic structure of Si and Ge nanocrystals | ||
| Iraqi Journal of Physics | ||
| Article 1, Volume 10, Issue 18, August 2012, Pages 127-134 | ||
| Authors | ||
| Ahmed M. Abdul-Lettif; Mudar A. Abdulsattar; Noor A. Nama; Noor H. Aysa | ||
| Abstract | ||
| Ab – initio restricted Hartree - Fock method within the framework of large unit cell (LUC) formalism is used to investigate the electronic structure of Si and Ge nanocrystals. The surface and core properties are investigated. A large unit cell of 8 atoms is used in the present analysis. Cohesive energy, energy gap, conduction and valence band widths are obtained from the electronic structure calculations. The results are compared with available experimental data and theoretical results of other investigators. The calculated lattice constant is found to be slightly larger than the corresponding experimental value because we use only 8 atoms and we compared the results with that of the bulk crystals, nanoclusters are expected to have stronger directional bonds that in their bulk structure. The surface states are found to be mostly non-degenerated because of the effect of surface discontinuity and the existence of oxygen atoms. Valence and conduction bands are found to be wider on the surface due to the splitting of energy levels due to the existence of oxygen atoms. The present method can be used to investigate the electronic structure of bulk, surface and nanocrystals. | ||
| Keywords | ||
| Nanocrystals; Surface; Electronic Structure | ||
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