Confining the growth of mesoporous silica films into nanospaces: towards surface nanopatterning.

The combination of lithographic methods and sol gel bottom-up techniques is a promising approach for nanopatterning substrates. The integration and scalable fabrication of such substrates are of great interest for the development of nanowire-based materials opening potentialities in new technologies. We demonstrate the deposition of ordered mesoporous silica into nanopatterned silica substrates by dip coating. Using scanning electron microscopy and grazing incidence small angle X-ray scattering, the effect of the sol composition on the pore ordering was probed. Optimising the sol composition using anodic alumina membranes as confined spaces, we showed how the pH controlled the transformation from circular to columnar mesophase. Vertical mesopores were obtained with very good repeatability. The effect of the sol chemistry on the surfactant curvature was then shown to be similar in nanopatterned substrates made by e-beam lithography.

Large-Area Electrodeposition of Few-Layer MoS2 on Graphene for 2D Material Heterostructures.

Heterostructures involving two-dimensional (2D) transition metal dichalcogenides and other materials such as graphene have a strong potential to be the fundamental building block of many electronic and optoelectronic applications. The integration and scalable fabrication of such heterostructures are of the essence in unleashing the potential of these materials in new technologies. For the first time, we demonstrate the growth of few-layer MoS2 films on graphene via nonaqueous electrodeposition. Through methods such as scanning and transmission electron microscopy, atomic force microscopy, Raman spectroscopy, energy- and wavelength-dispersive X-ray spectroscopies, and X-ray photoelectron spectroscopy, we show that this deposition method can produce large-area MoS2 films with high quality and uniformity over graphene. We reveal the potential of these heterostructures by measuring the photoinduced current through the film. These results pave the way toward developing the electrodeposition method for the large-scale growth of heterostructures consisting of varying 2D materials for many applications.