Publications: Articles
2015 | |
Articles: | |
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Electrochimica Acta,
174(0):376-383
2015
Mots clefs: In-situ ellipsometry nucleation electrocrystallization first steps of electrodeposition bismuth telluride Resume: Abstract An optical-electrochemical study on the initial stages of bismuth telluride (Bi2Te3) electrodeposition onto gold substrate is presented in this work. Numerical methods were applied on both electrochemical and optical data to obtain the relevant kinetic parameters from electrocrystallization theoretical equations and ellipsometric models in order to describe this system in the relevant 0-15 seconds range. The in-situ ellipsometry and electrodeposition analysis reveals a three-step mechanism. After an induction time including the double layer charge, the formation of a monolayer of tellurium is highlighted, followed by the adatom surface diffusion. Then, the growth of three-dimensional Bi2Te3 crystallites is observed according a progressive nucleation and a linear growth rate. Experimental and theoretical details about each technique are given and analyzed. Equipe: Département CP2S : Chimie et électrochimie des matériaux |
2014 | |
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Chemistry of Materials,
26(16):4765-4775
2014
Resume: We present a detailed study of the evolution of the electrical, galvanomagnetic, and thermodynamic properties of polycrystalline AgxMo9Se11 compounds for 3.4 ? x ? 3.8 at low temperatures (2?350 K). In agreement with density functional theory calculations, the collected data show an overall gradual variation in the transport properties from metallic to semiconducting behavior on going from x = 3.4 to 3.8. The results evidence subtle variations in the electronic properties with the Ag content, typified by both positive and negative phonon-drag effects together with thermopower and Hall coefficient of opposite signs. Analysis of the data suggests that these features may be due to peculiarities of the dispersion of the valence bands in the vicinity of the chemical potential. A drastic influence of the Ag content on the thermal transport was evidenced by a pronounced change in the temperature dependence of the specific heat below 10 K. Nonlinearities in the Cp(T3) data are correlated to the concentration of Ag atoms, with an increase in x resulting in a more pronounced departure from a Debye law. The observed behavior mirrors that of ionic conductors, suggesting that AgxMo9Se11 for x ? 3.6 might belong to this class of compounds. Equipe: Département CP2S : Chimie et électrochimie des matériaux |
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Thin Solid Films,
571, Part 3(0):509-512
2014
Mots clefs: Systematic errors In-situ ellipsometry Electrodeposition Bismuth telluride Resume: Abstract We describe a spectroscopic ellipsometer in the visible domain (400–800 nm) based on a rotating compensator technology using two detectors. The classical analyzer is replaced by a fixed Rochon birefringent beamsplitter which splits the incidence light wave into two perpendicularly polarized waves, one oriented at + 45° and the other one at ? 45° according to the plane of incidence. Both emergent optical signals are analyzed by two identical CCD detectors which are synchronized by an optical encoder fixed on the shaft of the step-by-step motor of the compensator. The final spectrum is the result of the two averaged ? and ? spectra acquired by both detectors. We show that ? and ? spectra are acquired without systematic errors on a spectral range fixed from 400 to 800 nm. The acquisition time can be adjusted down to 25 ms. The setup was validated by monitoring the first steps of bismuth telluride film electrocrystallization. The results exhibit that induced experimental growth parameters, such as film thickness and volumic fraction of deposited material can be extracted with a better trueness. Equipe: Département CP2S : Chimie et électrochimie des matériaux |
2012 | |
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Electrochimica Acta,
2012
Equipe: Département CP2S : Chimie et électrochimie des matériaux |
2009 | |
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Ultrasonics Sonochemistry,
16(2):266-272
2009
Equipe: Département CP2S : Chimie et électrochimie des matériaux |
2008 | |
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Physica Status Solidi C - Current Topics in Solid State Physics,
5(5):1190-1193
2008
Equipe: Département CP2S : Chimie et électrochimie des matériaux |
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Surface and Interface Analysis,
40(3-4):593-596
2008
Equipe: Département CP2S : Chimie et électrochimie des matériaux |
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Thin Solid Films,
516(10):2922-2927
2008
Equipe: Département CP2S : Chimie et électrochimie des matériaux |
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Scripta Materialia,
58(12):1058-1061
2008
Equipe: Département CP2S : Chimie et électrochimie des matériaux |
2007 | |
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Electrochimica Acta,
52(14):4760-4766
2007
Equipe: Département CP2S : Chimie et électrochimie des matériaux |