Browsing by Author "Atnafu, Ermias"

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    Size Dependent Band Gap Properties of Silicon Nanocluster with Hydrogen and Oxygen Passivated at the Surface
    (Addis Ababa University, 2007-04) Atnafu, Ermias
    Theoretical study of the electronic structure properties of silicon nanocluster (size5≤nanometer), in particular the role played by quantum confinement and hydrogen passivation have been studied using the empirical pseudo potential approximation method. We have calculated the gap energy of the nanocluster for different sizes between the highest occupied molecular orbital (HUMO) and the lowest unoccupied molecular orbital (LUMO). It is observed that quantum confinement effect plays the greatest role for HOMO LUMO gap difference i.e. as the number of atoms in the dot decreases; there is a considerable increase in the energy gap. Hydrogen passivation and addition of oxygen also widens the gap energy. We have compared our results with tight binding and other calculations. The agreement with other results confirms the validity of quantum confinement model gap enhancement that is responsible for visible luminescence in nanosilicon