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1

Structure and Relative Stability of Si_n (n=10-16) Clusters

100%

Mahtout S., Belkhir M.

Acta Physica Polonica A

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2006

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vol. 109

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issue 6

685-693

EN

Ab initio molecular dynamics simulated annealing technique coupled with density functional theory in the local density approximation implemented in Spanish initiative for electronic simulations with thousands of atoms method is employed to search the ground state geometries of silicon clusters containing 10-16 atoms. We found a number of new isomers which are not previously reported. The atoms in all these clusters exhibit pronounced preference for residing on the surface. The binding energies increase while the highest occupied-lowest unoccupied molecular orbital gap generally decreases with the increase in clusters size.

2

An ab initio Study of a Model of Single Wall GaN Nanotubes with Oxygen and Zinc as Impurities: Structural and Electronic Properties

100%

Rezouali K., Belkhir M.

Acta Physica Polonica A

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2008

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vol. 113

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issue 2

713-722

EN

We report a comprehensive theoretical study of structural and electronic properties of substitutional oxygen and zinc contaminations in a model of single wall GaN nanotubes by means of ab initio supercell calculations. Our investigation yields many interesting results. The following ones deserve to be developed. Oxygen forms a shallow donor in the single wall GaN nanotubes as in bulk GaN polytypes. Its ionization energy is deeper than its counterpart in the bulk wurtzite GaN, so it can be a suitable n-type dopant in high temperature applications. Zinc is a relatively shallow acceptor at gallium site. It behaves as charge carrier trap at nitrogen site. The site preference of zinc impurity depends on the stoichiometry. Zinc at gallium site has small ionization energy, thus it would be an efficient p-dopant in GaN nanotubes unlike in bulk GaN polytypes.

3

Fabrication and Characterization of Semiconductor CuCl Nanocrystals

81%

Mahtout S., Belkhir M., Samah M.

Acta Physica Polonica A

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2004

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vol. 105

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issue 3

279-286

EN

CuCl nanocrystals were elaborated in a NaCl ionic matrix by doping the latter with copper powder during growth. Optical absorption measurements revealed nanocrystals with a mean size of order 32 Å. This is consolidated by the Raman scattering measurements which showed nanodomains of similar size. X-ray diffraction measurements indicate a good crystallinity of the matrix and confirm the presence of CuCl nanocrystals within our samples. The annealing effect at 300˚C showed an increase in CuCl nanocrystal size with annealing time and demonstrated clearly the existence of a compound containing copper within our samples.

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3 Acta Physica Polonica A

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1 Rezouali K.

1 Samah M.

Structure and Relative Stability of Si_n (n=10-16) Clusters

An ab initio Study of a Model of Single Wall GaN Nanotubes with Oxygen and Zinc as Impurities: Structural and Electronic Properties

Fabrication and Characterization of Semiconductor CuCl Nanocrystals