We use ab initio simulations to study the static and dynamic properties of a sodium borosilicate liquid with composition 3Na2 O–B2 O3 –6SiO2 , i.e., a system that is the basis of many glass-forming materials. In particular, we focus on the question how boron is embedded into the local structure of the silicate network liquid. From the partial structure factors we conclude that there is a weak nanoscale phase separation between silicon and boron and that the sodium atoms form channel-like structures as they have been found in previous studies of sodosilicate glass-formers. Our results for the x-ray and neutron structure factor show that this feature is basically not detectable in the former but should be visible in the latter as a small peak at small wave vectors. At high temperatures we find a high concentration of threefold coordinated boron atoms which decreases rapidly with decreasing T , whereas the number of fourfold coordinated boron atoms increases. Therefore, we conclude that at the experimental glass transition temperature most boron atoms will be fourfold coordinated. We show that the transformation of [3] B into [4] B with decreasing T is not just related to the diminution of nonbridging oxygen atoms as claimed in previous studies, but to a restructuring of the silicate matrix. The diffusion constants of the various elements show an Arrhenius behavior and we find that the one for boron has the same value as the one of oxygen and is significantly larger than the one of silicon. This shows that these two network-formers have rather different dynamical properties, a result that is also confirmed from the time dependence of the van Hove functions. Finally, we show that the coherent intermediate scattering function for the sodium atoms is very different from the incoherent one and that it tracks the one of the matrix atoms.

For three different sizes of graphene nanosheets, we computed the Density of states when these nanosheets are progressively doped with an increasing percentage of Si atoms. The pure graphene nanosheets are semi conducting or not depending on their size. The pure silicene nanosheets are conducting with a conduction due to π electrons. The Si doped graphene nanosheets are also semi conducting or not depending on their size: for small sizes, there are semi conducting and they become conducting for larger sizes and larger percentages of Sidoping. We computed also the total electronic energy which is linked to the mechanical stability of all our nanosheets. This mechanical stability decreases regularly as a function of the Si percentage of doping , but for the pure silicene nanosheets, the mechanical stability decreases more abruptly.

Nanostructured Zn1−xVxO (0 ⩽ x ⩽ 0.50) thin films were synthesized by rf-magnetron sputtering at two different substrate temperatures (room temperature (RT) and 200 °C) and with variable sputtering powers (60, 80 and 100 W). In this method, single targets based on Zn1−xVxO nanopowders prepared by the sol–gel process were used. Characterization of the Zn1−xVxO nanoparticles showed that they crystallize in the hexagonal wurtzite structure. Their size ranged from 20 to 40 nm. The effect of process parameters on the physical and chemical properties of Zn1−xVxO thin films has been studied. For x ⩽ 0.30, the results obtained at 200 °C and 60 W indicate that the films have a high quality of crystallinity. Vegard’s law is respected, indicating that vanadium is incorporated in the ZnO matrix. The chemical compositions of these films were found to be close to the stoichiometry. The films exhibit a columnar structure and a smooth surface. Their average transmission, from the visible to the NIR, was in the range of 75–90%. The values of the band gap of the Zn1−xVxO thin films with x ⩽ 0.30 and elaborated at 200 °C and 60 W, vary from 3.29 to 3.74 eV. This is consistent with blue shifting of near-band edge cathodoluminescence emission. Under particular growth conditions, the investigation shows that the Zn0.80V0.20O sample presents the best properties for potential use in various optoelectronic applications, namely: a single wurtzite phase, low surface roughness (Ra ∼ 0.2 nm), a high transparency of 90% in the UV–Vis–NIR, a wide band gap of 3.74 eV and a resistivity of ∼5 × 10+3 Ω cm.