Unite de Recherche de Physique des Semiconducteurs et Capteurs

Al Marsá, Tunisia

Unite de Recherche de Physique des Semiconducteurs et Capteurs

Al Marsá, Tunisia

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Benrabah B.,Université Ibn Khaldoun | Bouaza A.,Université Ibn Khaldoun | Kadari A.,Oran University of Science and Technology - Mohamed Boudiaf | Maaref M.A.,Unite de Recherche de Physique des Semiconducteurs et Capteurs
Superlattices and Microstructures | Year: 2011

Antimony-doped tin oxide thin films have a range of technological applications as conductive coatings, and sol-gel processing seems to offer some advantages over other coating techniques. In this study antimony-doped tin oxide (ATO) thin films have been prepared by the sol-gel dip-coating (SGDC) process, using tin (II) chloride dehydrate (SnCl2, 2H2O) and antimony (III) chloride (SbCl3) as host and dopant precursors respectively. The structure of the (ATO) powders was analysed by X-ray diffraction (XRD) and the microstructure of the thin films by atomic force microscopy (AFM). These investigations show that the structure is tetragonal rutile type and that an increase in Sb-doping decreases the crystallite size of the (ATO) particles. To analyze the impedance spectroscopy data, the Nyquist (Z″ vs. Z′) plots as well as the representation of imaginary (Z″) and real (Z′) parts of impedance vs. frequency were used. The Nyquist plots suggest that only the grain boundaries are responsible in the conduction mechanism of the material. From the variation of lnσ vs. inverse of absolute T we have deduced the activation energy found to be 0.87 eV. © 2011 Elsevier Ltd. All rights reserved.


Helali S.,Unite de Recherche de Physique des Semiconducteurs et Capteurs | Abdelghani A.,Unite de Recherche de Physique des Semiconducteurs et Capteurs | Jaffrezic-Renault N.,CNRS Analytical Sciences Lab | Trikalitis P.N.,University of Crete | And 2 more authors.
Electrochimica Acta | Year: 2010

The development of a vanadium pentoxide xerogel (VXG)-based sensor for the detection of volatile inorganic (ammonia) and organic (dimethylamine, etc.) amines is described. The xerogel film was deposited on interdigitated gold electrodes by dip-coating using an aqueous solution of VXG. The morphology of the sensing layer, its interaction with ammonia, which was used as a model analyte throughout this work, as well as the regeneration of the surface of the sensor electrodes with vapors of HCl were examined with scanning electron microscopy and FTIR spectroscopy. Signal changes, due to changes of the RC-product of the electrochemical cell (Au-VXG-Au), as a result of its interactions with ammonia vapors, were probed with a portable, homemade charge meter, the Multipulser. Exposing the sensor electrodes to various concentrations of ammonia vapors resulted in proportional changes in the signal output. Finally, the proposed sensors were successfully used for on-site, real-time monitoring of fish spoilage in ambient conditions. © 2009 Elsevier Ltd. All rights reserved.


Bergaoui Y.,Unite de Recherche de Physique des Semiconducteurs et Capteurs | Fourati N.,French National Conservatory of Arts and Crafts | Zerrouki C.,French National Conservatory of Arts and Crafts | Fougnion J.-M.,French National Conservatory of Arts and Crafts | Abdelghani A.,Unite de Recherche de Physique des Semiconducteurs et Capteurs
Instrumentation Mesure Metrologie | Year: 2011

A gravimetric surface acoustic wave (SAW) sensor associated to two independent measurement techniques (oscillator and pulse excitation modes) has been developed and realized. After SAW performances characterization, we have developed an immunosensor, based on the biotin-streptavidin-antistreptavidin recognitions. The SAW biosensor presented a sensitivity of 0.25°/nM and a specific recognition of antistreptavidin. Nevertheless, the presence of Horseradish peroxidise (HRP) causes a binding kinetics reduction by a factor up to 5, as well as a diminution of saturation value of 56 %. © 2011 Lavoisier, Paris.


Bergaoui Y.,Unite de Recherche de Physique des Semiconducteurs et Capteurs | Zerrouki C.,French National Conservatory of Arts and Crafts | Fourati N.,French National Conservatory of Arts and Crafts | Fougnion J.M.,French National Conservatory of Arts and Crafts | Abdelghani A.,Unite de Recherche de Physique des Semiconducteurs et Capteurs
EPJ Applied Physics | Year: 2011

A gravimetric surface acoustic wave (SAW) biosensor, based on the biotin-streptavidin and antistreptavidin-streptavidin recognitions, has been carried out. A network analyser and a pulse excitation technique were used to monitor both amplitude and phase changes. The SAW biosensor presented a total selective recognition of streptavidin-antistreptavidin and HRPstreptavidin- antistreptavidin. The presence of HRP (Horseradish peroxidase) affects neither the selectivity nor the sensitivity (of order of 0.25°/nM) of the biosensor, nevertheless, it causes a reduction of binding kinetics by a factor ranging between 2 to 5, as well as a diminution of antistreptavidin saturation concentration (of 40%). Results showed that equilibrium constants can be different, depending on evaluation method (from saturation values or from linear part of the output signal variation according to solution concentration). © EDP Sciences, 2011.


Arfaoui A.,Tunis el Manar University | Ouni B.,Tunis el Manar University | Touihri S.,Tunis el Manar University | Mhamdi A.,Tunis el Manar University | And 2 more authors.
Optical Materials | Year: 2015

Molybdenum oxide thin films were thermally evaporated on a glass substrate and monitored by an annealing process in a variable oxygen atmosphere. The effects of post annealing condition on the microstructural, morphological, optical and electrical properties were investigated using X-ray diffraction, Raman spectroscopy, atomic force microscope, spectroscopic ellipsometry and impedance spectroscopy. As-deposited amorphous films crystallized into tetragonal metastable phase of Mo5O14 on annealing at 500°C in vacuum and air. This structure transformed to stable orthorhombic of MoO3 with annealing in oxygen environment. The optical parameters such as the refractive index, extinction coefficient, optical band gap energy and the Urbach energy were calculated from Cauchy formalism. Ellipsometric measurements reveal that the samples present optical gap located between 3.24 and 3.90 eV when the atmosphere becomes rich on oxygen. The variation of the conductivity in terms of the temperature shows an electrical behavior with oxygen environment. Finally, it has been found that MoO3 thin films had high sensitivity to ethanol, which made them as a good candidate for the ethanol sensor. © 2015 Elsevier B.V. All rights reserved.

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