Stefano Borini
Nokia
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Featured researches published by Stefano Borini.
Nanoscale | 2015
A. C. Ferrari; Francesco Bonaccorso; Vladimir I. Fal'ko; K. S. Novoselov; Stephan Roche; Peter Bøggild; Stefano Borini; Vincenzo Palermo; Nicola Pugno; Jose A. Garrido; Roman Sordan; Alberto Bianco; Laura Ballerini; Maurizio Prato; Elefterios Lidorikis; Jani Kivioja; Claudio Marinelli; Tapani Ryhänen; Alberto F. Morpurgo; Jonathan N. Coleman; Valeria Nicolosi; Luigi Colombo; M. García-Hernández; Adrian Bachtold; Grégory F. Schneider; F. Guinea; Cees Dekker; Matteo Barbone; Zhipei Sun; C. Galiotis
We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.
Applied Physics Letters | 2009
Matteo Bruna; Stefano Borini
We show that the optical constants of graphene in the visible range can be estimated by means of a very simple procedure involving their consistence with universal optical conductivity and experimentally measured optical spectra, within the framework of Fresnel coefficients calculation. The obtained complex refractive index allows for accurate prediction of the optical behavior of graphene in the visible range, from the two-dimensional limit (single atomically thick graphene layer) to the bulk limit (graphite). Therefore, it may result very useful for quantitative optical analysis of graphene layers and graphitic structures in general.
Applied Physics Letters | 2001
Andrea M. Rossi; Giampiero Amato; Vittorio Camarchia; Luca Boarino; Stefano Borini
This letter reports a method to produce porous-silicon waveguides by means of a laser local oxidation process. The estimated losses of the waveguides are below 1 dB/cm. This demonstrates the applicability of this material in integrated optics and telecommunications. Moreover, our results disclose the opportunity to integrate optoelectronic devices onto Si substrates. The laser writing method is achievable at low laser power, thus it is highly efficient and achievable with the standard equipment present in most laboratories. Another advantage is that oxidation is achieved without heating the complete chip, thus simplifying the integration process, i.e., the oxidation is inherently local through the direct-write process. This method opens the opportunity to build microstructures, like channel and membrane filters, in a flexible manner by R&D laboratories.
Physical Review B | 2010
Matteo Bruna; Stefano Borini
An experimental study of Raman scattering in N-layer graphene as a function of the top layer doping is reported. At high doping level, achieved by a CHF3 plasma treatment, we observe a splitting of the G band in the spectra of bilayer and 4-layer graphene (N even), whereas the splitting is not visible in case of monolayer and trilayer graphene (N odd). The different behaviors are related to distinct electron-phonon interactions, which are affected by symmetry breaking and Fermi-level position in different ways in the various N-layer graphenes. In trilayer graphene, a weakening of the electron-phonon coupling as a function of the Fermi energy induces a hardening of all zone-center in-plane optical-phonon modes, such as in monolayer graphene. On the other hand, in 4-layer graphene two distinct trends are observed in the G band as a function of doping, suggesting the presence of two different groups of electron-phonon interactions, such as in bilayer graphene
Journal of Materials Chemistry | 2011
Matteo Bruna; Barbara Massessi; Cristina Cassiago; A. Battiato; E. Vittone; Giorgio Speranza; Stefano Borini
Covalent bond-forming reactions can be used to tailor the properties of graphene, aiming at electronic band structure engineering and surface functionalization. We present a novel and easy method for the production of chemically modified monolayer graphene based on the electrochemical intercalation of graphite, that could be used for adding various functional groups to the graphene lattice. Oxy-fluorinated graphene layers have been produced and fully characterized in terms of their chemical composition and functionalization. Moreover, Raman spectroscopy allows ready discrimination between monolayers and few-layers, and field-effect devices have been fabricated in order to study the transport properties of monolayer graphene oxyfluoride. Interesting conduction mechanisms such as two dimensional Mott variable range hopping and colossal negative magneto-resistance are observed, making this novel material suitable for both fundamental research and graphene-based applications.
Journal of Physics D | 2009
Matteo Bruna; Stefano Borini
We show that contrast analysis carried out by standard optical microscopy can be employed as a simple and quick technique to monitor the cleanness of graphene during the process steps required for device fabrication. Graphene flakes deposited by adhesive tape exfoliation can display a strong contrast increase upon processing, due to the organic contamination arising from the diffusion of glue residues over the samples. On the other hand, graphene deposited by an adhesive-free method, such as electrostatic deposition, does not show any contrast variation, suggesting a low degree of contamination. Therefore, the fabrication process of graphene-based devices may be monitored and optimized on the basis of an easy optical inspection.
Lab on a Chip | 2005
Stefano Borini; Sabato D'Auria; Mosè Rossi; Andrea M. Rossi
A three-dimensional protein nanopatterning method has been developed, based on local activation of porous silicon by electron beam. Proteins specifically bind to irradiated regions, and the depth of biomolecule nanopatterns can be controlled by varying the electron energy. This unique feature permits exploitation of the huge surface area of the sponge-like material, thus allowing concentration of a large amount of proteins on nanosized patterns. Moreover, the grafted biomolecules retain their full functionality, and the feasibility of a glucose sensor has been demonstrated.
Physical Review B | 2013
D. Gatto Monticone; F. Quercioli; R.Mercatelli Rmercatelli; S. Soria; Stefano Borini; T. Poli; Maurizio Vannoni; E. Vittone; P. Olivero
We report on the systematic characterization of photoluminescence (PL) lifetimes in NV- and NV0 centers in 2 MeV H+ implanted type Ib diamond samples by means of a time correlated single photon counting (TCSPC) microscopy technique. A dipole-dipole resonant energy transfer model was applied to interpret the experimental results, allowing a quantitative correlation of the concentration of both native (single substitutional nitrogen atoms) and ion-induced (isolated vacancies) PL-quenching defects with the measured PL lifetimes. The TCSPC measurements were carried out in both frontal (i.e. laser beam probing the main sample surface along the same normal direction of the previously implanted ions) and lateral (i.e. laser beam probing the lateral sample surface orthogonally with respect to the same ion implantation direction) geometries. In particular, the latter geometry allowed a direct probing of the centers lifetime along the strongly nonuniform damage profiles of MeV ions in the crystal. The extrapolation of empirical quasi-exponential decay parameters allowed the systematic estimation of the mean quantum efficiency of the centers as a function of intrinsic and ion-induced defect concentration, which is of direct relevance for the current studies on the use of diamond color centers for photonic applications.
Journal of Physics: Condensed Matter | 2006
Sabato D’Auria; Marcella de Champdoré; Vincenzo Aurilia; Antonietta Parracino; Maria Staiano; Annalisa Vitale; Mosè Rossi; Ilaria Rea; Lucia Rotiroti; Andrea M. Rossi; Stefano Borini; Ivo Rendina; Luca De Stefano
Small analytes such as glucose, L-glutamine (Gln), and ammonium nitrate are detected by means of optical biosensors based on a very common nanostructured material, porous silicon (PSi). Specific recognition elements, such as protein receptors and enzymes, were immobilized on hydrogenated PSi wafers and used as probes in optical sensing systems. The binding events were optically transduced as wavelength shifts of the porous silicon reflectivity spectrum or were monitored via changes of the fluorescence emission. The biosensors described in this article suggest a general approach for the development of new sensing systems for a wide range of analytes of high social interest.
Applied Physics Letters | 2006
Stefano Borini; Luca Boarino; Giampiero Amato
The resistivity of (100)-oriented mesoporous silicon has been studied using two different electrode configurations. The authors observed that the electronic transport along the longitudinal direction (parallel to the sample surface) is strongly inhibited at room temperature but not along the perpendicular direction. They show that such electrical anisotropy can be removed by heating the material, reporting an increase of six orders of magnitude of the longitudinal conductivity when the temperature rises from 20to100°C. These experimental findings are interpreted on the basis of the material morphology and nanostructuration, which determine the availability of percolative pathways for free charge carriers.