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Abbassi A.,Mohammed V University | Ez-Zahraouy H.,Mohammed V University | Benyoussef A.,Mohammed V University | Benyoussef A.,Institute for Nanomaterials and Nanotechnology
Optical and Quantum Electronics | Year: 2015

Optical properties of ZnO doped with Silicon and Aluminum were studied by first principle calculations using the density functional theory. The optical absorption, transmittance and optical constants are investigated using the full potential-linearized augmented plane wave method with the generalized gradient approximation and mBJ approximation, implemented in Wien2k package. With the mBJ approximation the direct optical gap of a pure ZnO is about 3.34 eV, which is in good agreement with experimental results. The behavior of the transmittance and the absorption of the Al-doped ZnO are higher and better than those of the Si-doped ZnO. The transmittance of Al-doped ZnO is stable and high in the visible light range and can reach 96 % at 400 nm. This confirms the physical characteristics that can present Al to be used as suitable transparent material electrodes in solar cells. © 2014, Springer Science+Business Media New York.

Houmad M.,Mohammed V University | Dakir O.,Mohammed V University | Abbassi A.,Mohammed V University | Benyoussef A.,Mohammed V University | And 4 more authors.
Optik | Year: 2016

Electronic and optical properties of silicon carbide nanosheet (2D monolayer) have been studied using full potential linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA) within WIEN2k package. The dielectric tensor is derived within the random phase approximation (RPA). The electronic structure and the optical properties of SiC nanosheet such as the dielectric function, reflectivity, absorption coefficient and optical conductivity are calculated for both perpendicular and parallel electric field polarizations. © 2015 Elsevier GmbH.

Risite H.,Mohammed V University | Risite H.,Institute for Nanomaterials and Nanotechnology | El Mabrouk K.,Euro-Mediterranean University | Bousmina M.,Euro-Mediterranean University | And 3 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2016

The relationship between the morphological observations and the physical properties of polyamide 11 (PA11)/clay nanocomposites prepared by melt processing was investigated with a special interest on the use of various contents of silane modified PA11 (PA-m-Si). PA-m-Si was prepared using 1 wt% of 3-aminopropyltriethoxysilane (APTES) added to PA11 in reactive extrusion. The morphological observations by TEM and XRD are presented in conjunction with the rheological and mechanical properties of these nanocomposites. The addition of PA-m-Si generated a net favorable interaction with organoclay that permitted higher level of exfoliation/intercalation resulting from a balance of component interactions. XRD spectra of nanocomposites revealed that the increase of PA-m-Si induced a decrease in peak intensities at high clay loadings (≥5 wt%) which informed about a reduction of stacks intercalated structure leading to a higher degree of delamination and a larger increase of aspect ratio of clay. The rheological properties suggest that the extent of a percolation network can be enhanced by increasing the degree of exfoliation/intercalation at fixed clay content. The tensile and thermal properties were also found to be improved in all cases. Copyright © 2016 American Scientific Publishers All rights reserved.

Houmad M.,Mohammed V University | Zaari H.,Mohammed V University | Benyoussef A.,Mohammed V University | Benyoussef A.,Institute for Nanomaterials and Nanotechnology | And 3 more authors.
Carbon | Year: 2015

The linear optical and electronic properties of a monolayer graphene sheet are investigated using the Density Functional Theory within the Full Potential Linearized Augmented Plane Wave (FP-LAPW) formalism. Three approaches are used in this work: The Generalized Gradient Approximation (GGA), the Tran-Blaha modified Becke-Johnson exchange potential approximation (TB-mBJ); implemented in WIEN2K code; and GW (Green function G and screened Coulomb interaction W) implemented in Yambo code. The band gap of graphene with and without silicon doping and the effect of silicon on optical properties of graphene are calculated. The silicon doping opens the band gap of graphene and increases its optical conductivity. This material may be used in solar cell application. Other optical properties such as reflectivity and refractive index are also studied. © 2015 Elsevier Ltd. All rights reserved.

Mejdoubi A.,Institute for Nanomaterials and Nanotechnology | Mejdoubi A.,Moroccan Foundation for Advanced Science and Innovation and Research MAScIR | Malki M.,Institute for Nanomaterials and Nanotechnology | Malki M.,Moroccan Foundation for Advanced Science and Innovation and Research MAScIR | And 7 more authors.
Journal of Applied Physics | Year: 2011

Three-dimensional finite-difference time-domain simulations are used to study the near- and far-field properties of plasmonic core-shell (CS) nanostructures of reduced symmetry. Special attention is given to silica core and gold shell nanoparticles by changing their geometry. For the simulated range of wavelengths (300-2100 nm) our calculations of the scattering and absorption efficiencies imply strong polarization sensitivity and are highly dependent on the size and geometry of the CS nanostructures. Strong enhancements of the exciting electric field associated with the excitations of nanoparticle plasmons are observed. The wavelength dependence of the scattering spectra and concentration of electromagnetic field in subwavelength volumes have a potential for biosensing and bioimaging. © 2011 American Institute of Physics.

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