The Instituto de Ciencia de Materiales de Madrid (ICMM) is an institute of the Consejo Superior de Investigaciones Cientificas (CSIC) (Spanish National Research Council) founded in December 1986, that belongs to the Area of Science and Technology of Materials, one of the eight Areas in which the CSIC divides its research activities.
Our mission is to create new fundamental and applied knowledge in materials of high technological impact, their processing and their transfer to the productive sectors at local, national and European scales (the true value of materials is in their use), the training of new professionals, and the dissemination of the scientific knowledge.
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From single-molecule experiments to a general framework for non-equilibrium thermodynamics
Graphene–ultrasmall silver nanoparticle interactions and their effect on electronic transport and Raman enhancement
F. Jimenez-Villacorta, E. Climent-Pascual, R. Ramirez-Jimenez, J. Sanchez-Marcos, C. Prieto and A. de Andrés
The modulation of electrical and Raman properties of ultrafine (∼4 nm) Ag nanoparticle/graphene/SiO2 hybrid material at low coverage is evaluated with gradual nanoparticle incorporation by the gas aggregation deposition technique. The different contributing factors, such as doping, impurity scattering or strain, are assessed. Incorporation of Ag nanoparticles produce a very efficient n-type doping of graphene (∼7.5 e- per particle) maintaining a constant mobility for particle coverage below ∼0.3 monolayers. Doping efficiency is determined by the probability for nanoparticles to be deposited in contact with graphene. The Fermi level upshift is modeled within the charged impurity scattering mechanism in the whole coverage range. A crossover to the regime where impurity scattering dominates is evidenced at large particle concentration. Surface-enhanced Raman scattering is detected in graphene phonons in the limit of vanishing plasmon resonance and very low coverage (∼0.08) that correspond to ∼1500 nanoparticles at the laser spot. Small distortions of the graphene lattice (±0.012%) induced by the nanoparticles overcome the predicted changes in Raman phonons related to carrier doping and originate I2D/IG damping. This evolution of physical properties with gradual incorporation of Ag nanoparticles is anticipated to provide valuable hints to tune the optical and electronic performance of these graphene-based hybrid systems.
AFM images of the Ag nanoparticle/graphene sample at different deposition times; (b) height histogram representing the size distribution, fitted with a log-normal function; (c) representative height profile at t = 30 s, to illustrate the average particle size distribution; (d) representative height profile at t = 90 s, showing the incipient nanoparticle pile-up on previously deposited nanoparticles