Ricerc@Sapienza

The progressive miniaturisation of electronic and optoelectronic devices has heightened the interest for ultrathin and flexible materials. Research in this field received a tremendous boost with the discovery of graphene, a single, atomically-thin layer of carbon atoms.
Graphene can be isolated from graphite thanks to the weak van der Waals (vdW) forces which bind the different layers together. In addition to graphite, many other vdW crystals were discovered in the past decade, and many other atomically-thin crystals were isolated. The latter typically possess unique properties, due to the enhanced quantum effects related to their two-dimensional (2D) nature.
If vdW materials in their 2D form have already revealed extraordinary potentialities per se, new rich scenarios are envisaged by creating 2D heterostructures (HSs).
Conventional HSs such as Si/Ge, InGaP/GaP, etc., have been the essential elements in modern semiconductor research and industry but their growth is limited by lattice mismatch constraints. On the other side, 2D crystals bind together via weak vdW forces and 2D HSs can thus be assembled layer-by-layer with unprecedented tunability.
Within this context, HSs based on 2D semiconducting materials are particularly interesting since coupling phenomena between the different layers were shown to lead to a strong light emission, which is promising for optoelectronic applications.
Few material combination were however studied and the exploration of this wide field has just commenced.
Here, we propose to exploit novel atomically-thin semiconductors for the fabrication of new HSs. Besides the most well-known 2D semiconductors, we will exploit 2D alloys, which were recently synthesised and whose physical properties are still not well-studied. Optical studies will first allow us to characterise the electronic and spin properties of these materials. The fabrication of alloy-based HSs will then allow us to create light emitting sources with engineered properties.