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Graphene molecular junctions


  1. From Electroburning to Sublimation: Substrate and Environmental Effects in the Electrical Breakdown Process of Monolayer Graphene
    Maria El Abbassi, Laszlo Posa, Peter Makk, Cornelia Nef, Kishan Thodkar, Andras Halbritter, and M. Calame.
    Nanoscale, 9(44), 17312-17317, {2017} publisher ="The Royal Society of Chemistry" [DOI] [Abstract]

    We report on the characterization of the Electrical Breakdown (EB) process for the formation of tunneling nanogaps in single-layer graphene. In particular{,} we investigated the role of oxygen in the breakdown process by varying the environmental conditions (vacuum and ambient conditions). We show that the density of oxygen molecules in the chamber is a crucial parameter that defines the physical breakdown process: at low density{,} the graphene lattice is sublimating{,} whereas at high density the process involved is oxidation{,} independent on the substrate material. To estimate the activation energies of the two processes{,} we use a scheme which consists of applying voltage pulses across the junction during the breaking. By systematically varying the voltage pulse length{,} and estimating the junction temperature from a 1D thermal model{,} we extract activation energies which are consistent with the sublimation of graphene in high vacuum and the electroburning process in air. Our study indicates that a better control of the gaps formation is suitable in the sublimation regime.

  2. Multiple physical timescales and dead time rule in few-nm sized graphene-SiOx-graphene memristors
    Laszlo Posa, Maria El Abbassi, Peter Makk, Botond Santa, Cornelia Nef, Miklos Csontos, Michel Calame, and Andras Halbritter.
    Nano Letters, , null, 2017 [DOI]
  3. Electrolyte gate dependent high-frequency measurement of graphene FETs for sensing applications
    W. Fu, El M. Abbassi, T. Hasler, M. Jung, M. Steinacher, M. Calame, and C. Schoenenberger.
    Appl. Phys. Lett., 104, 13102, 2014 [DOI]