Electronic properties of nanostructured thin films

Electronic properties of nanostructured thin films

The control of the composition and morphology of materials at the nanoscale allowed to disclose novel structural, electronic and chemical properties which are fundamental for many recent technological advances. Amongst nanostructures, 2D materials are a class formed of materials which cryistallise as atomically-thin layers. Since the discovery of graphene in the early 2000s, the family of 2D materials grew larger, with the emergence of new systems alike the hexagonal boron nitride (hBN) or the black phosphorus (BP).

Because of their extreme thinness, 2D materials often display electronic properties sizeably different from those of their bulk equivalent. Moreover, their characteristics are strongly influenced by the interaction with the near surroundings: for instance by modifications of the substrate, or changes of their thickness. Van der Waals heterostructures are based on this principle. They are built by stacking layers of different 2D materials on top of each other, so that several properties are combined in the same system and tuned in a controlled fashion. This allows to engineer specific properties aimed for technological development or fundamental research.

In this context, we will consider heterostructures based on hBN and/or BP layers. In order to study these systems from a theoretical perspective, we will elaborate a mixed approach combining analytical and numerical developments in the tight-binding formalism, with ab-initio simulations. The latter will be done on simple reference systems, with the intent to establish a quantitative basis for the parametrization of tight-binding models. This will make possible the investigation of extended systems like realistic heterostructures. More precisely, the objectif will be that of studying the influence of the environment (substrate, stacking …) on the electronic and optical properties of van der Waals heterostructures based on hBN and BP.

Another specificity of this work will consist on coupling the theoretical study with diverse experimental techniques, namely thanks to our rich collaboration network.

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