N. Abbouni

Publications (2)1.32 Total impact

• Article: Structural and electronic properties of chalcopyrite semiconductors AgXY2 (X = In, Ga; Y = S, Se, Te) under pressure

  A. Chahed, O. Benhelal, H. Rozale, S. Laksari, N. Abbouni
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  ABSTRACT: Results are presented of a first-principles calculation of the direct band-gap pressure coefficient ag for a series of Al, Ga and In chalcopyrite semiconductor compounds AgXY2 (X = Ga, In; Y = S, Se, Te) and the corresponding zinc-blende structure. Good agreement was found between the calculated and experimental pressure coefficients. It was found that ag in chalcopyrites are dramatically reduced relative to zinc-blende compounds, and that the Al → Ga → In substitution lowers ag in chalcopyrites more than in zinc-blende compounds. As a result, the empirical rule suggested for zinc-blende compounds, stating that for a given transition (e.g. Γ15v → Γ1c) ag does not depend on substitutions, has to be modified for chalcopyrites. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
  physica status solidi (b) 09/2006; 244(2):629 - 634. · 1.32 Impact Factor
• Article: First-principles calculations of the structural, electronic and optical properties of CuGaS2 and AgGaS2

  S. Laksari, A. Chahed, N. Abbouni, O. Benhelal, B. Abbar
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  ABSTRACT: The structural, electronic and optical properties of two chalcopyrite crystals: CuGaS2 and AgGaS2 are studied using the full potential linearized augmented plane waves method within the local density approximation (LDA). Geometrical optimization of the unit cell (equilibrium volume, c/a ratio, internal parameter u, and bulk modulus) is in good agreement with experimental data. The energy gap is found to be direct for both materials and the nature of the gap crucially depends on the manner in which the Ga 3d and (Ag 4d, Cu 3d) electrons are treated as valence states. Results on band structures and density of states are presented. We report also our results on optical properties like the complex dielectric functions and the refractive index n of the CuGaS2 and AgGaS2 crystals. We analyze in detail the structures of the dielectric function observed in the studied energy region.
  Computational Materials Science.