The Experts below are selected from a list of 192 Experts worldwide ranked by ideXlab platform
J. L. Lemaire - One of the best experts on this subject based on the ideXlab platform.
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Interaction of D2 with H2O amorphous ice studied by temperature-programed desorption experiments
Journal of Chemical Physics, 2006Co-Authors: L. Amiaud, J. Fillion, S. Baouche, F. Dulieu, A. Momeni, J. L. LemaireAbstract:The gas-surface interaction of molecular hydrogen D 2 with a thin film of porous amorphous solid water ͑ASW͒ grown at 10 K by slow vapor deposition has been studied by temperature-programed-desorption ͑TPD͒ experiments. Molecular hydrogen diffuses rapidly into the porous network of the ice. The D 2 desorption occurring between 10 and 30 K is considered here as a good probe of the effective surface of ASW interacting with the gas. The desorption kinetics have been systematically measured at various coverages. A careful analysis based on the Arrhenius plot method has provided the D 2 binding energies as a function of the coverage. Asymmetric and broad distributions of binding energies were found, with a maximum population peaking at low energy. We propose a model for the desorption kinetics that assumes a complete thermal equilibrium of the molecules with the ice film. The sample is characterized by a distribution of adsorption sites that are filled according to a Fermi-Dirac Statistic law. The TPD curves can be simulated and fitted to provide the parameters describing the distribution of the molecules as a function of their binding energy. This approach contributes to a correct description of the interaction of molecular hydrogen with the surface of possibly porous grain mantles in the interstellar medium.
L. Amiaud - One of the best experts on this subject based on the ideXlab platform.
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Interaction of D2 with H2O amorphous ice studied by temperature-programed desorption experiments
Journal of Chemical Physics, 2006Co-Authors: L. Amiaud, J. Fillion, S. Baouche, F. Dulieu, A. Momeni, J. L. LemaireAbstract:The gas-surface interaction of molecular hydrogen D 2 with a thin film of porous amorphous solid water ͑ASW͒ grown at 10 K by slow vapor deposition has been studied by temperature-programed-desorption ͑TPD͒ experiments. Molecular hydrogen diffuses rapidly into the porous network of the ice. The D 2 desorption occurring between 10 and 30 K is considered here as a good probe of the effective surface of ASW interacting with the gas. The desorption kinetics have been systematically measured at various coverages. A careful analysis based on the Arrhenius plot method has provided the D 2 binding energies as a function of the coverage. Asymmetric and broad distributions of binding energies were found, with a maximum population peaking at low energy. We propose a model for the desorption kinetics that assumes a complete thermal equilibrium of the molecules with the ice film. The sample is characterized by a distribution of adsorption sites that are filled according to a Fermi-Dirac Statistic law. The TPD curves can be simulated and fitted to provide the parameters describing the distribution of the molecules as a function of their binding energy. This approach contributes to a correct description of the interaction of molecular hydrogen with the surface of possibly porous grain mantles in the interstellar medium.
K. Gärtner - One of the best experts on this subject based on the ideXlab platform.
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Existence of bounded discrete steady state solutions of the van Roosbroeck system with monotone Fermi–Dirac Statistic functions
Journal of Computational Electronics, 2015Co-Authors: K. GärtnerAbstract:If in the classic van Roosbroeck system (Bell Syst Tech J 29:560–607, 1950 ) the Statistic function is modified, the equations can be derived by a variational formulation or just using a generalized Einstein relation. In both cases a dissipative generalization of the Scharfetter–Gummel scheme (IEEE Trans Electr Dev 16, 64–77, 1969 ), understood as a one-dimensional constant current approximation, is derived for strictly monotone coefficient functions in the elliptic operator $$\nabla \cdot { {f}(v)} \nabla $$ ∇ · f ( v ) ∇ , v chemical potential, while the hole density is defined by $$p={\mathcal {F}}(v)\le e^v.$$ p = F ( v ) ≤ e v . A closed form integration of the governing equation would simplify the practical use, but mean value theorem based results are sufficient to prove existence of bounded discrete steady state solutions on any boundary conforming Delaunay grid. These results hold for any piecewise, continuous, and monotone approximation of $${ {f}(v)}$$ f ( v ) and $${\mathcal {F}}(v)$$ F ( v ) . Hence an implementation based on this discretization will inherit the same stability properties as the Boltzmann case based on the Scharfetter–Gummel scheme. Large chemical potentials and and related degeneracy effects in semiconductors can be approximated. A proven, stability focused blueprint for the discretization of a fairly general, steady state Fermi–Dirac like drift–diffusion setting for semiconductors using mainly new results to extend classic ideas is the main goal.
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Existence of bounded discrete steady state solutions of the van Roosbroeck system with monotone Fermi---Dirac Statistic functions
Journal of Computational Electronics, 2015Co-Authors: K. GärtnerAbstract:If in the classic van Roosbroeck system (Bell Syst Tech J 29:560---607, 1950) the Statistic function is modified, the equations can be derived by a variational formulation or just using a generalized Einstein relation. In both cases a dissipative generalization of the Scharfetter---Gummel scheme (IEEE Trans Electr Dev 16, 64---77, 1969), understood as a one-dimensional constant current approximation, is derived for strictly monotone coefficient functions in the elliptic operator $$\nabla \cdot { {f}(v)} \nabla $$?·f(v)?, v chemical potential, while the hole density is defined by $$p={\mathcal {F}}(v)\le e^v.$$p=F(v)≤ev. A closed form integration of the governing equation would simplify the practical use, but mean value theorem based results are sufficient to prove existence of bounded discrete steady state solutions on any boundary conforming Delaunay grid. These results hold for any piecewise, continuous, and monotone approximation of $${ {f}(v)}$$f(v) and $${\mathcal {F}}(v)$$F(v). Hence an implementation based on this discretization will inherit the same stability properties as the Boltzmann case based on the Scharfetter---Gummel scheme. Large chemical potentials and and related degeneracy effects in semiconductors can be approximated. A proven, stability focused blueprint for the discretization of a fairly general, steady state Fermi---Dirac like drift---diffusion setting for semiconductors using mainly new results to extend classic ideas is the main goal.
Abderrazzak El Boukili - One of the best experts on this subject based on the ideXlab platform.
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A Posteriori Error Estimators for Linearized Semiconductor Equations with Mixed Finite Elements Approach in $H(\div) \times L^2$
1995Co-Authors: Abderrazzak El Boukili, Manolo Castro-diazAbstract:In the framework of Mixed Finite Element Methods, the mathematical analysis of an error indicator, which relies on the residual of a linearized Drift-Diffusion model of the transport equation for electrons in heterojunction semiconductor devices using Fermi-Dirac Statistic, is presented. Just now, no numerical experiences have been carried out in order to prove the efficiency of the proposed isotropic estimator. However, from its numerical interpretation, it appears that they are coherent and well indicate the boundary layer and abrupt hetrerojunction problems.
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A Posteriori Error Estimators for Linearized Semiconductor Equations with Mixed Finite Elements Approach in . . .
1995Co-Authors: Abderrazzak El Boukili, Manolo Castro-diaz, Projet MenusinAbstract:: In the framework of Mixed Finite Element Methods, the mathematical analysis of an error indicator, which relies on the residual of a linearized Drift-Diffusion model of the transport equation for electrons in heterojunction semiconductor devices using Fermi-Dirac Statistic, is presented. Just now, no numerical experiences have been carried out in order to prove the efficiency of the proposed isotropic estimator. However, from its numerical interpretation, it appears that they are coherent and well indicate the boundary layer and abrupt hetrerojunction problems. Key-words: Automatic mesh adaptation, Mixed finite elements, Abrupt heterojunction semiconductors, Transport equations (for electrons), Drift-Diffusion model, Local error indicators, Isotropic mesh. (R'esum'e : tsvp) Email : Abderrazzak.ElBoukili@inria.fr Email : Castro.Diaz@inria.fr Unite de recherche INRIA Rocquencourt Domaine de Voluceau, Rocquencourt, BP 105, 78153 LE CHESNAY Cedex (France) Telephone : (33 1) 39 63 5..
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Arclength continuation methods and applications to 2D drift-diffusion semiconductor equations
1995Co-Authors: Americo Marrocco, Abderrazzak El Boukili, Projet MenusinAbstract:: In this paper, the homotopy deformation method to solve the nonlinear stationary semiconductor equations with Fermi-Dirac Statistic is used. This method introduces an artificial transient problem. The time discretization is based on the nonlinear implicit scheme with local time steps. In order to have an automatic adaptation of local time step parameters, we introduce arclength predictor-corrector continuation methods. The fondamental goal of these methods is to overcome the unstabilities or the failure of the classical Newton-Raphson's schemes which appear when the nonlinearity is Strong or near Limit or Bifurcation points. The approximate procedure of our system using a Galerkin method that makes use of a mixed finite element approach is used. A peculiar feature of this mixed formulation is that the electric displacement D and the current densities j n and j p for electrons and holes, are taken as unknowns, together with the potential OE and quasi Fermi levels OE n and OE p . This..
F. Dulieu - One of the best experts on this subject based on the ideXlab platform.
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Interaction of D2 with H2O amorphous ice studied by temperature-programed desorption experiments
Journal of Chemical Physics, 2006Co-Authors: L. Amiaud, J. Fillion, S. Baouche, F. Dulieu, A. Momeni, J. L. LemaireAbstract:The gas-surface interaction of molecular hydrogen D 2 with a thin film of porous amorphous solid water ͑ASW͒ grown at 10 K by slow vapor deposition has been studied by temperature-programed-desorption ͑TPD͒ experiments. Molecular hydrogen diffuses rapidly into the porous network of the ice. The D 2 desorption occurring between 10 and 30 K is considered here as a good probe of the effective surface of ASW interacting with the gas. The desorption kinetics have been systematically measured at various coverages. A careful analysis based on the Arrhenius plot method has provided the D 2 binding energies as a function of the coverage. Asymmetric and broad distributions of binding energies were found, with a maximum population peaking at low energy. We propose a model for the desorption kinetics that assumes a complete thermal equilibrium of the molecules with the ice film. The sample is characterized by a distribution of adsorption sites that are filled according to a Fermi-Dirac Statistic law. The TPD curves can be simulated and fitted to provide the parameters describing the distribution of the molecules as a function of their binding energy. This approach contributes to a correct description of the interaction of molecular hydrogen with the surface of possibly porous grain mantles in the interstellar medium.