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Djebara M.,University of Science and Technology Houari Boumediene | Stoquert J.P.,Institute of Electronics of Solids and Systems | Abdesselam M.,University of Science and Technology Houari Boumediene | Muller D.,Institute of Electronics of Solids and Systems | Chami A.C.,University of Science and Technology Houari Boumediene
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2012

The degradation induced by MeV He + ions onto polyethylene terephthalate (PET) is investigated as a function of fluence and electronic stopping power (dE/dx) e. Stack samples of four 3.6 μm PET films are irradiated by 3.5 MeV He + under vacuum and room temperature at fluence ranging from 10 13 to 1.5 × 10 15 He + cm -2. The entrance energies range from 3.5 MeV for the front film to 0.573 MeV for the rear one at the beginning of the irradiation and the corresponding mean (dE/dx) e lie for pristine PET between 158 and 264 keV/μm. A Fourier transform infrared spectroscopy (FTIR) analysis is undertaken. The different stack films present similar damages with magnitude increase as the fluence goes up. Moreover, higher is the electronic stopping power (dE/dx) e more important is the damage. The evolution of the normalized integrated absorbance A(φ)/A 0 of the internal reference 1410 cm -1 band as a function of the fluence φ presents a complex behavior characterized by a two-exponential decay associated to low and high fluence range. The analysis reveals clearly that the A(φ)/A 0 of the characteristic benzene ring 1577 cm -1 band remains steady till fluence around 3 × 10 14 He + cm -2 and then decreases smoothly as fluence increases. The band appearing at 1610 cm -1, assigned to mono substituted benzene, presents an integrated absorbance A(φ) which rises progressively and levels off beyond a critical fluence around 4 × 10 14 He + cm -2. The cross section of the creation of the monosubstituted benzene lies between 3 × 10 -15 and 6 × 10 -15 cm 2 for (dE/dx) e = 158 and 264 keV/μm, respectively. Drastic loss of crystallinity is induced by the MeV He + ion irradiation in the polymer. The amorphization is monitored by the evolution of the specific bands of the trans and gauche ethylene glycol residue conformations. A sudden drop in the integrated absorbance of the 1340 cm -1 band which characterizes the trans conformation is observed at fluence around 2 × 10 14 He + cm -2. On the other hand, a drastic increase is present in the integrated absorbance of the gauche conformation 1370 cm -1 band that pairs up with 1340 cm -1 band. This observation is a clear indication of the conversion of the trans ethylene glycol residue to gauche one under irradiation. © 2011 Elsevier B.V. All rights reserved.


Paviet-Salomon B.,French National Solar Energy Institute | Gall S.,French National Solar Energy Institute | Monna R.,French National Solar Energy Institute | Manuel S.,French National Solar Energy Institute | And 4 more authors.
Energy Procedia | Year: 2011

Phosphorus-doped silicon nitride (SiN(P)) layers have been investigated as dopant sources for laser-induced diffusion. Their optical properties were measured and revealed that reflectivity and refractive index were weakly affected by adding phosphorus (P) and that SiN(P) layers could consequently be used as anti-reflection coatings. These layers were also found to offer efficient surface passivation regardless of the introduced P quantity. Laser doping (LD) and thermal annealing (TA) were then carried out and showed that a wide doping range can be obtained from SiN(P) layers using both driving-in methods. Selective emitter solar cells were then processed using TA to realize the thin emitter and LD to pattern the heavily-doped areas to be metalized. Though cells results need to be further improved, SiN(P) layers appear to be extremely promising as dopant sources for low-thermal budget selective emitter solar cells processing. © 2010 Published by Elsevier Ltd.


Kabir A.,Skikda University | Meftah A.,Skikda University | Stoquert J.P.,Institute of Electronics of Solids and Systems | Toulemonde M.,University of Caen Lower Normandy | Monnet I.,University of Caen Lower Normandy
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

In our previous work [15], we have evidenced, using RBS-C, two effects in the aluminium sublattice of sapphire irradiated with 90.3 MeV xenon ions: a partial disorder creation that saturates at ∼40% followed above a threshold fluence by a highly disordered layer appearing behind the surface. In this work, by RBS-C analysis of the oxygen sublattice, we have observed only one regime of partial disorder creation that saturates at ∼60% in tracks of cross-section double of that found for the aluminium sublattice. Complementary analysis by X-ray diffraction shows that the lattice strain increases with the fluence until a maximum is reached about 7.5 × 1012 ions/cm2. For higher fluences, strain decreases first indicating a little stress relaxation in the material and tends afterwards, to remain constant. This stress relaxation is found to be related to the aluminium sublattice high disorder. © 2010 Elsevier B.V. All rights reserved.


Dadouche F.,Institute of Electronics of Solids and Systems | Bethoux O.,University Paris - Sud | Kleider J.-P.,University Paris - Sud
Energy | Year: 2011

In this article, we aim at optimizing an innovative tandem structure based on polymorphous and microcrystalline silicon for the top and bottom elementary cells, respectively, combined with an original DC-DC converter. The studied tandem structure is composed of two cells, each being connected to its own separate electrodes making the structure electrically decoupled but optically coupled. In those conditions, the constraint of current matching usually needed in the classical micromorph structures is avoided. As a result, the robustness against the current variations is enhanced and the efficiency of the structure is improved. Since the top cell plays the main role in the determination of the transmitted part of the incoming flux to the bottom cell, the thickness of the intrinsic layer of the polymorphous cell is tuned so that the output power of the global structure becomes maximal. To implement the electric decoupling of two sub cells, the studied structure needs two static converters. In order to minimize the converters bulk, we design an innovative output electric architecture and its optimized related control signals. © 2011 Elsevier Ltd.


Rotaru C.,University of Caen Lower Normandy | Pawlak F.,University of Caen Lower Normandy | Khalfaoui N.,University of Caen Lower Normandy | Dufour C.,University of Caen Lower Normandy | And 5 more authors.
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2012

Vitreous silica thin film (a-SiO 2) and mixed deuterated and hydrogenated amorphous carbon thin film (a-C:D,H), grown or deposited, respectively, on silicon, have been irradiated at GANIL in the MeV/u energy range with ions between C and U in order to reach electronic energy loss between 0.7 and 25 keV/nm. The evolution of Si-O bonds and C-D bonds contents was determined by infrared absorption spectroscopy. Complementary physico-chemical characterization was performed for a-C:D,H using Rutherford backscattering spectrometry (RBS) and elastic recoil detection analysis (ERDA). For a-SiO 2, the band at 1076 cm -1 decreases with the appearance of a band at 1046 cm -1. In the case of the diamond like amorphous carbon, the main effects due to MeV/u ion irradiations are the decrease of sp 3 bonding content and of deuterium relative concentration (D/C atomic ratio) as a function of fluence with the appearance of the sp 1 bond. The cylinder radii in which these physical phenomena are confined can be deduced from a statistical analysis. Using the inelastic thermal spike model (i-TS) these track radii can be described using the electron-phonon mean free path which takes values equal to 3 and 0.9 nm for a-SiO 2 and a-C:D, respectively. Extrapolation to low energy range (∼1 MeV in total or ∼0.02 MeV/u) will be made. © 2011 Elsevier B.V. All rights reserved.


Avasthi D.K.,Inter University Accelerator Center | Mishra Y.K.,Institute for Materials Science | Singh F.,Inter University Accelerator Center | Stoquert J.P.,Institute of Electronics of Solids and Systems
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms | Year: 2010

Swift heavy ions have unique feature of creating ion tracks in insulators of dimension from a few nm to about 10 nm. This particular feature of the swift heavy ions is used to engineer the size and shape of the nanoparticles embedded in silica matrix. On the basis of several experiments, it is evidenced that the embedded nanoparticles either grow in size or reduce in size, if they are smaller than or comparable to the ion track size. The shape transformation from spherical to elongated along the beam direction occurs, when the nanoparticle size is larger than the ion track diameter in silica. The reduction, growth and elongation of Au nanoparticles embedded in silica matrix under swift heavy ion irradiation have been discussed in the frame work of thermal spike model. © 2010 Elsevier B.V. All rights reserved.


Armeanu D.,Institute of Electronics of Solids and Systems | Leroy Y.,Institute of Electronics of Solids and Systems | Cordan A.-S.,Institute of Electronics of Solids and Systems
Physica Status Solidi (C) Current Topics in Solid State Physics | Year: 2011

The purpose of this paper is to report the results of a study on single electron charging of a nanocrystal floating gate in a metal-oxide-semiconductor transistor. Our model is based on the geometrical and physical parameters of hypothetically spherical nanocrystals embedded in oxide (nanocrystal radius, distance between nanocrystals, oxide thickness, bulk band structure). This model can be numerically solved through a two-dimensional finite element approach. The channel and gate electrodes are described through energy subbands, and the silicon nanocrystal through discrete energy levels. Two types of tunnel transport are considered here: indirect tunneling from the channel to the nanocrystal and then from the nanocrystal to the gate, and direct tunneling from the channel to the gate. We show that the latter type can be neglected for the current range of nanocrystal densities used for memory applications. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Zaiour A.,Lebanese University | Hamie A.,Lebanese University | Hage-Ali M.,Institute of Electronics of Solids and Systems
Physics Procedia | Year: 2014

Several attempts were made during the last 3 decades to improve the quality of CdTe in order to enhance its efficiency as material for nuclear and photovoltaic devices. These attempts considered the high values of impurity segregation coefficients and the contamination problems due to handling at high temperature. In this study, we prepared three high purity CdTe single crystals with high resistivity. The three starting Te samples were purified through three purification processes: horizontal zone refining, vacuum distillation, and by combining both processes. Purities were characterized, by determining the concentration of 22 impurities by Atomic Absorption (AASGF), for the three kinds of tellurium ingots and the corresponding elaborated CdTe materials. A series of four effective segregation coefficients for metallic impurities: Ag, Al, Cu, and Fe were found in CdTe. Their high values confirmed the difficulty to remove them by the purification processes using the segregation phenomenon. In addition, the low concentration values of impurities in CdTe samples (6N purity) make from our CdTe high quality electronic grade materials. © 2014 Elsevier B.V.


Madec M.,Institute of Electronics of Solids and Systems
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2012

This paper deals with the development of a new simulator that will be very helpful to establish new accurate and predictive design-oriented models for the BioBricks used in synthetic biology. The simulator uses the principle of the game-of-life: molecules can move on a grid and, at every iteration, binding and dissociation rules are applied when two molecules are on same node. The principle is elementary but it can highlight interesting biological phenomenon. Those can be modeled by mathematical equations to achieve design-oriented models. In this case, the simulator also helps to make to link between mathematical parameters and the microscopic parameters. A first version of the software has been implemented in MATLAB. It permits to retrieve very interesting results, such as the Hill's equation and the properties of Hill's coefficient.


Gendrault Y.,Institute of Electronics of Solids and Systems
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference | Year: 2012

Synthetic bio-systems become increasingly more complex and their development is lengthy and expensive. In the same way, in microelectronics, the design process of very complex circuits has benefited from many years of experience. It is now partly automated through Electronic Design Automation tools. Both areas present analogies that can be used to create a Genetic Design Automation tool inspired from EDA tools used in digital electronics. This tool would allow moving away from a totally manual design of bio-systems to assisted conception. This ambitious project is presented in this paper, with a deep focus on the tool that automatically generates models of bio-systems directly usable in electronic simulators.

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