New paper on nanogap formation in graphene is accepted to Nanoscale! Congratulations to Maria!

Congratulations to Maria!

Paper about the  study of environmental effects on the nanogap in graphene formation was just accepted for publication to Nanoscale!

• From Electroburning to Sublimation: Substrate and Environmental Effects in the Electrical Breakdown Process of Monolayer Graphene
  Abbassi, Maria El, Laszlo Posa, Peter Makk, Cornelia Nef, Kishan Thodkar, Andras Halbritter, and Michel Calame.

  Nanoscale 9 (44) , 17312-17317 (2017) .
  [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.