Multi-scale strategy for high-k/metal-gate UTBB-FDSOI devices modeling with emphasis on back bias impact on mobility

Mobility in high-k/metal-gate Ultra-Thin Body and Box Fully Depleted SOI devices has been extensively investigated by means of multi-scale simulations and experimental data. Split-CV mobility measurements have been performed for various Interfacial Layer Equivalent Oxide Thickness allowing an investigation of the physical mechanisms responsible for the mobility degradation at high-k/Interfacial layer interface. The impact of the back bias on transport properties is investigated and mobility enhancement in the reverse regime (back gate inversion) is studied. A multi-scale simulation strategy is ranging from quantum Non-equilibrium Green’s Functions to semi-classical Kubo Greenwood approach. These advanced solvers made possible a throughout calibration of empirical TCAD mobility models.     

Traumatic pulmonary hernia: surgical versus conservative management

B cells are characterized by the dual expression of CD40 and Fas receptors, which can mediate their survival and death, respectively. The balance between the dynamically opposing functions of these two receptors is important for B-cell selection, maturation and homeostasis. We found that mantle cell lymphoma (MCL) cells had a high level of CD40 and low or absent level of Fas, therefore favouring the CD40 cell survival pathway. Exogenous Fas ligand had no effect on MCL cells, whereas exogenous CD40 ligand enhanced their survival and rescued them from fludarabine-induced apoptosis. Our data raise the possibility that the prolonged survival of MCL cells in vivo may be explained by the unbalanced expression of Fas and CD40.     

Optimisation of a model food mixture using response surface methodology to evaluate the anti‐adhesive properties of cooking materials

The composition of a model food was optimised to evaluate the anti‐adhesive properties of cooking materials. This optimisation was performed using a response surface methodology. When cooked at 201 °C, the model food was selected to leave the greatest quantity of cooked residue that cannot be removed easily from the utensil surface. The measurement of the surface covered by the cooked food left after cleaning was the response value of the experimental design. The effect of five macronutrients was evaluated. Glucose and ovalbumin factors showed the most important positive effect, while amylopectin presented a negative effect. The optimum concentration values of the food constituents where highest food adsorption was estimated were 34.5 mg mL^?1 glucose, 14.5 mg mL^?1 amylopectin, 39.0 mg mL^?1 ovalbumin, 13.5 mg mL^?1 casein and 32.8 mg mL^?1 linoleic acid. The predicted results at the optimum point coincided well with experimental values. The optimum food mixture presented good precision as well.     

Confinement effects and tunnelling through quantum dots

Several recent theoretical advances concerning semiconductor quantum dots are reviewed. First of all, the effect of the quantum confinement on the energy gap is revisited on the basis of GW and Bethe-Salpeter calculations, showing that the excitonic gap is practically equal to the ordinary eigenvalue gap of single-particle approximations. The second part demonstrates that it is now possible to calculate the conductance peaks for the tunnelling current through a nanostructure. Finally, we discuss in some detail the concept of a macroscopic dielectric constant for nanostructures, showing that, except for a thin surface layer, the local dielectric constant still keeps its bulk value down to pretty small nanostructures.     

Mécanisme d'émission électronique dans les structures mim et propagation des électrons dans les métaux

The distribution of electrons emitted by MIM structures has been measured by recording an electron image on a photographic plate. Electrons are emitted into vacuum by “formed” structures when a negative voltage is applied to the outer metal films.The escape depth of the electrons emitted by “unformed” structures does not depend on the applied voltage. We conclude that the energy distribution of the electrons injected into the outer electrode does not depend on the applied voltage.     

Effects of a shell on the electronic properties of nanowire superlattices

We compute the structural and electronic properties of core-shell InAs/GaAs nanowire superlattices using Keating's valence force field and a sp3d5s* tight-binding model. We show that the GaAs shell limits strain relaxation but homogenizes the hydrostatic strain distribution in the InAs layers. This prevents the formation of a strain-induced well in the conduction band at the surface of the nanowires, which was shown to trap the electrons in thin InAs layers (Phys. Rev. B 2006, 74, 155304). The shell, however, enhances the piezoelectric field, which increases the separation between the electrons and holes in thick InAs layers. These results emphasize the intricate links between the structural and electronic properties of strained nanowire heterostructures.     

Highly defective graphene: A key prototype of two-dimensional Anderson insulators

Electronic structure and transport properties of highly defective two-dimensional (2D) sp² graphene are investigated theoretically. Classical molecular dynamics are used to generate large graphene planes containing a considerable amount of defects. Then, a tight-binding Hamiltonian validated by ab initio calculations is constructed in order to compute quantum transport within a real-space order-N Kubo-Greenwood approach. In contrast to pristine graphene, the highly defective sp² carbon sheets exhibit a high density of states at the charge neutrality point raising challenging questions concerning the electronic transport of associated charge carriers. The analysis of the electronic wavepacket dynamics actually reveals extremely strong multiple scattering effects giving rise to mean free paths as low as 1 nm and localization phenomena. Consequently, highly defective graphene is envisioned as a remarkable prototype of 2D Anderson insulating materials.