123 person-months secondments have been executed, and the principal objectives of the project reached.
More than 80 articles, 33 of which involved two or more project teams, were published in high-impact international journals. Many other articles are in preparation or submitted.
Our scientific results include:
- The formation of silicene on graphene grown on graphitized 4H-SiC(0001) and on highly oriented pyrolytic graphite (HOPG) as template substrate was investigated. Synthesis route consists of evaporating silicon under ultrahigh vacuum conditions (UHV) keeping the substrate at room temperature. In the same experimental chamber, the samples were characterized with STM, STS and XPS. From the experiments and theoretical calculations, we observed three different stable configurations on HOPG: (i) formation silicene nanosheets, (ii) 3D clusters, and (iii) Si 2D nanosheets intercalated below the first top layer of carbon atoms
- The morphology of the Dirac meta-atoms was studied by combining SEM and optical microscopy techniques. This allowed us to reveal the dependence of the carbon shell thickness, roughness and porosity on the synthesis parameters. The continuity of the Dirac semimetals shells was investigated by using STM, AFM and HRTEM measurements. The electrical conductivity of the deposited shells was compared with that obtained for plane samples.
- We showed that smooth electron waveguides in tilted Dirac materials can be used to manipulate the degree of valley polarization of quasiparticles travelling along a particular direction of the channel. We examine the particular case of the hyperbolic secant potential to model realistic top-gated structures for valleytronic applications.
- We studied theoretically optical properties of emerging two‐dimensional (2D) materials and metamaterials with tilted Dirac cones in the electronic band structure and developed an optical recipe to fully characterize the tilt and Fermi velocity anisotropy of any 2D tilted Dirac cone solely from its absorption spectrum. We expect this work to encourage Dirac cone engineering as a major route to create gate-tunable thin-film polarizers.
- We have developed and characterized triboelectric nanogenerators consisting of triboelectric layers obtained from composite materials of (1) bamboo+starch and (2) bamboo+starch+graphene water suspensions. We observed that the addition of graphene improves the power density generation.
- The efficient ultra-thin electromagnetic absorber based on an array of multi-layered graphene hemispheres was fabricated by combining 3D ink-jet printing, electroplating and chemical vapor deposition processes. These submicron thick metasurfaces demonstrate almost perfect absorption, > 95%, in very broad frequency range. They are also robust against macroscopic structural defects, i.e. their electromagnetic properties remain the same when structure comprises up to 40% of randomly distributed holes and other geometrical imperfectness.
Dissemination:
more than 40 actions, including newspaper interviews, popular books, and dissemination at schools
Exploitation:
the following studies have been identified as under-development innovations with possible industrial/medical/societal/technological applications:
- Prototypes of tunable and ultrathin (less than 1 micron thick) THz lens and filters that outperform existing ones in terms of footprint
- The broadband absorbing graphene structures with extraordinarily aging and wear resistance that open a way for hostile environment applications
- The Si3N4 membrane enhanced with pyrolyzed graphitic 20 nm thick PyC film open new opportunities for design of novel ultrabroad band bolometric radiation detectors
- The C-shaped polymer metasurfaces with extraordinary focus performance capable to maintain focusiong ability when subjected to bending
- Graphene-enhanced THz grating fabricated by femtosecond micromachined SiO2 substrate
- The negligible influence of the grain size on the performance of the graphene-based metasurfaceces and metamaterials was demonstrated
