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Jarraya K.,University of Sfax | Ennaceur N.,University of Sfax | Ennaceur N.,Laboratoire Of Physique Of La Matire Condense | El Marssi M.,Laboratoire Of Physique Of La Matire Condense | Mhiri T.,University of Sfax
Physica B: Condensed Matter

The elaborate mixed material of the formula NaH 2(PO 4) 0.48(AsO 4) 0.52·H 2O denoted by NDAP belongs to a group of compounds having properties that are intermediate between those of a normal salt and an acid, and undergoes a transition from a paraelectric to a superprotonic phase transition at room temperature. The temperature phase transition (296 K) leading to a superionicprotonic phase characterized by an unusual high conductivity at room temperature was found. The conductivity relaxation parameters associated with the high-disorder protonic conduction have been determined from the analysis of the M″/M″ max spectrum and measured in a wide temperature range. Transport properties in this material appear to be due to proton hopping mechanism. © 2011 Elsevier B.V. All rights reserved. Source

Jebbari N.,Laboratoire Of Physique Of La Matire Condense | Ouertani B.,Institute Suprieur Des Science Et Technology Of Lenvironnement Of Borj Cedria | Ramonda M.,Montpellier University | Guasch C.,Montpellier University | And 2 more authors.
Energy Procedia

Structural properties of CuIn(1-x)AlxS2 layers obtained by spray pyrolysis on various substrates were studied using X Ray Diffraction, Atomic Force Microscopy and Scanning electron microscopy. The concentration of Al in the spray solution, represented by the ratio z (z=[Al3+][In3+]), was varied from 0 to 3.2%. The different substrates are: glass, ZnO/glass, SnO2glass, ZnOSnO2glass and In 2S3Glass. All the layers were deposited by spray. The ZnO used in the substrates was doped with indium. The concentration of indium in the ZnO sprayed solution is [In][Zn]=3%. The X-ray diffraction spectra revealed that, different values of the ratio z, the CuIn(1-x)Al xS2 thin films were well crystallized in the tetragonal structure of the CuInS2 material with the privileged orientation (112) whatever the substrate. The surface topography of the CuIn (1-x)AlxS2 thin films, deduced from the Atomic Force Microscopy, proved that the grain size in the top of the layers depends both on the z value and on the substrate. The Auger analysis has been done in order to get information on the surface layer composition, the measurement show that the surface chemical composition where improved by annealing. In this work the performances of the solar cell CuIn(1-x)AlxS 2(p)CuInS2(p)In2S3(n)ZnO, realized with optimized value of Al concentration, is also presented. © 2009 Published by Elsevier Ltd. Source

Triki M.,Laboratoire Of Physique Of La Matire Condense | Elmaghraoui D.,Laboratoire Of Physique Of La Matire Condense | Jaziri S.,Laboratoire Of Physique Of La Matire Condense | Jaziri S.,Laboratoire Of Physique Et Des Matriaux | Bennaceur R.,Laboratoire Of Physique Of La Matire Condense
Solid State Communications

Using a numerical method via the electron effective mass theory, a model of a quantum ring (QR) with a shape very close to the real one and taken from an experimental work, we investigate the electron states in a semi-conductor QR, studying the influence of the ring's geometrical parameters on the electron spectrum and on the optical transitions. Our hetero structure evolves from a single quantum dot (QD) to a QR. We find that the one-electron ground state presents an absolute minimum when studied as a function of the ring radius. The reliability of the calculations is checked with experimental data. © 2010 Elsevier Ltd. All rights reserved. Source

Kamoun Allouche N.,Laboratoire Of Physique Of La Matire Condense | Kamoun Allouche N.,Montpellier University | Ben Nasr T.,Laboratoire Of Physique Of La Matire Condense | Kamoun Turki N.,Laboratoire Of Physique Of La Matire Condense | Castagne M.,Montpellier University
Energy Procedia

Thin films of copper indium disulfide (CuInS2) are deposited on various substrates (In2S3ZnOSnO2glass, ZnOSnO2glass), where In2S3 will be used as the optical window, ZnO as the optical window or wafer layer, CuInS2 as the absorber material in photovoltaic system and SnO2 as the ohmic contact. In2S3 is grown by chemical bath deposition; CuInS2, ZnO and SnO2 are grown by airless spray technique. The substrate temperature and the deposition duration of CuInS2 thin layer are fixed at 340 °C and 20 minutes respectively. The films were characterized by X-ray diffraction, Scanning electron microscope (SEM) and spectrophotometer. The X-ray diffraction revealed that the as-sprayed CuInS 2 absorber films are of chalcopyrite crystalline phase with a highly (112) preferential orientation, the In2S3 deposited by CBD have a (400) preferential orientation, the ZnO sprayed thin films crystallizes in the hexagonal wurtzite form with a (002) principal orientation and the SnO2 films are well crystallized in the tetragonal structure and oriented preferentially in the (200) direction. The SEM showed that the thickness of the SnO2, ZnO, In2S3 and CuInS2 are 0.529; 0.684; 0.267 and 0.507 μm respectively. The optical band gap of the CuInS2 absorber material is 1,51 eV. The electrical properties of these structures are analysed from current-voltage (I-V) characteristics. © 2009 Published by Elsevier Ltd. Source

Alibart F.,Laboratoire Of Physique Of La Matire Condense | Lejeune M.,Laboratoire Of Physique Of La Matire Condense | Durand Drouhin O.,Laboratoire Of Physique Of La Matire Condense | Zellama K.,Laboratoire Of Physique Of La Matire Condense | Benlahsen M.,Laboratoire Of Physique Of La Matire Condense
Journal of Applied Physics

We discuss in this paper the evolution of both the density of states (DOS) located between the band-tail states and the DOS around the Fermi level N (EF) in amorphous carbon nitride films (a-CNx) as a function of the total nitrogen partial pressure ratio in the Ar/ N2 plasma mixture. The films were deposited by three different deposition techniques and their microstructure was characterized using a combination of infrared and Raman spectroscopy and optical transmission experiments, completed with electrical conductivity measurements, as a function of temperature. The observed changes in the optoelectronic properties are attributed to the modification in the atomic bonding structures, which were induced by N incorporation, accompanied by an increase in the s p2 carbon bonding configurations and their relative disorder. The electrical conductivity variation was interpreted in terms of local effects on the nature and energy distribution of π and π states. © 2010 American Institute of Physics. Source

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