ARTEMIS’ core consisted in the fabrication and characterization of lateral spin valves (LSV) devices operating through graphene/molecule interfaces. For such a purpose, mechanically exfoliated graphene flakes were chosen, due to their excellent spin transport performance, as compared to the characteristics of graphene sheets grown by chemical vapor deposition (CVD). Manganese phthalocyanine (Mn-pc) molecules were selected for the interface design, as they demonstrated good air stability after evaporation on top of graphene. Besides, the surface characterization of the evaporated films demonstrated uniform coverage of films as thin as 5 nm. The fabrication of the LSV devices was optimized in order to be able to compare the properties of bare graphene sheets with the behavior of the graphene/molecule interfaces. Such a goal was achieved by taking advantage of a high precision stamping system for deterministic transfer of Van der Waals materials. The stamping process allowed half of the graphene channel to be protected with a flake of hexagonal boron nitride (hBN), which is an insulating Van der Waals material. In such a way half of the LSV channel was exposed to the evaporation of molecules while the other half was protected by the hBN capping. Such a strategy is particularly important in order to understand the changes induced by the evaporated molecules on the graphene channel, by comparing with the properties of the channel fabricated with the very same graphene flake. The electrical characterization of the graphene/molecule LSV showed that spin transport can be achieved through such interfaces as well as in the bare graphene channel. Yet, the results also show that the spin orbit coupling in graphene is not affected by the presence of the Mn-pc molecules. Instead, the presence of the molecules seems to affect the transport properties of graphene by inducing a sizeable charge doping.
Additionally, ARTEMIS has also focused on the optimization of graphene electrodes to be integrated in the design of organic field-effect transistor (OFET). The fabricated devices demonstrated optimal performance characteristics and constituted a positive contribution to the advance of all-organic based electronics. Such work has resulted in a published research article.
Finally, ARTEMIS resources were also dedicated to further investigation on graphene-based spintronic devices. LSV combining graphene with Van der Waals insulating (Cr2Ge2Te6) and metallic (FeGeTe3) Van der Waals magnets were designed and fabricated. The purpose of such heterostructures consisted in the achievement of injection of a spin current in graphene through all-Van der Waals interface. However, attempts to achieve electrical contacts through the Van der Waals magnets have failed, so that further optimization is needed for advancing in the measurements.
