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International audience; We use multiscale modelings to investigate the heat dissipation in 2D transistors based on phosphorene and silicene. First, molecular dynamics (MD) simulations were used to calculate the thermal interface resistance R int between the 2D materials (phosphorene and silicene) and dielectrics substrates (SiO 2 and TiO 2). The calculated R int of these systems are close to that between graphene and SiO 2 and are insensitive to the temperature. The MD values then served as inputs for finite-element simulations at the device scale. It is found that the heat-dissipation ability of the 2D transistors can be improved by increasing the thermal conductivities of the 2D materials as well as of the substrate. However, in contrast to the common belief, it is difficult to largely reduce the hot-spot temperature by tuning the interface thermal resistance. Finally, we show that the cooling performance of silicene/SiO 2 system can be significantly improved with a few-layer graphene heat spreader. These results provide important information for the novel design of 2D transistors in terms of thermal management.

International audience; Among the existing methods, Nanoimprint Lithography (NIL) emerges as a simple route for surface patterning at the sub-micrometer scale over large areas. Thanks to their tunable properties, sol-gel materials form an alternative class of resist for NIL. However, there is only little understanding of the rheological properties responsible for their good imprint ability. Based on previous works on thermal curing of thermosets, this paper establishes a framework which can be used to tune the imprint conditions and to apprehend the rheological properties of complex hybrids materials. Using a combination of Dynamic Mechanical Analysis (DMA) and scratch test, we were able to model the thermorheological behavior of Methyltriethoxysilane (MTES) gel films during isothermal treatments in a time-temperature-transformations (TTT) diagram. Infrared spectroscopy study of the gel demonstrates the existence, for the same elaboration chemistry, of a condensation threshold independent of the temperature above which the material vitrifies: this reveals the closed relation between the rheology and the chemical microstructure of the gel. We also discussed the strong influence of the elaboration chemistry on the initial microstructure and therefore on the vitrification.