Who: Marco Gobbi, Nanodevices group
Place: nanoGUNE seminar room, Tolosa Hiribidea 76, Donostia - San Sebastian
Date: Monday, 1 October 2018, 11:00
Van der Waals heterostructures, composed of vertically stacked inorganic 2D materials, represent an ideal platform to demonstrate novel device architectures and to fabricate on-demand materials. The incorporation of molecules within these systems holds an immense potential, since an almost infinite variety of molecules can be designed and synthesized with predictable functionalities. Here, we show how molecular design can be exploited to modify intrinsic properties and confer new capabilities to 2D materials. In a first work, we show that programmable 1D periodic potentials take place at the interface between ordered molecular layers and graphene, which might introduce anisotropy in the graphene band structure. The amplitude and sign of the potentials can be modified without altering their periodicity by employing different molecules.  In a second work, we demonstrate how the photo-responsive nature of molecular switches can be conferred to the charge transport properties of 2D materials. In particular, photochromic molecules self-assembled on graphene and MoS2 generate atomically precise superlattices in which a light-induced structural reorganization enables control over the local charge carrier density. Accordingly, novel device functionalities are demonstrated, including the photo-modulation of the threshold voltage in MoS2 and the use of spatially confined light irradiation to define reversible lateral heterojunctions. These experiments provide a glimpse of the potential of combining 2D materials with molecular monolayers to build up novel multifunctional materials with unique properties.