Source: https://www.unibas.ch/de/Aktuell/News/Uni-Info/Neue-Informatik-Assistenzprofessorin.html

Her paper on the  study of memristive behavior in SiOx-graphene nanojunction is just appeared in Nano Letters!

• Multiple physical timescales and dead time rule in few-nm sized graphene-SiOx-graphene memristors
  Posa, Laszlo, Maria El Abbassi, Peter Makk, Botond Santa, Cornelia Nef, Miklos Csontos, Michel Calame, and Andras Halbritter.

  Nano Letters , null (2017) .

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.

His paper, entitled “Restoring the electrical properties of CVD graphene via physisorption of molecular adsorbates”, was just accepted to ACS Applied Materials & Interfaces!

• Restoring the electrical properties of CVD graphene via physisorption of molecular adsorbates
  Kishan Thodkar, Damien Thompson, Felix Lüönd, Lucas Moser, Frédéric Overney, Laurent Marot, Christian Schönenberger, Blaise Jeanneret, and Michel Calame.
  ACS Applied Materials & Interfaces (ja), null (2017)

Dr. Mathias Wipf during his doctoral (2010-2014, University of Basel) studies and postdoctoral research job (2015-2016, Yale University, Mark Reed group) worked with silicon nanowire based sensors.

Dr. Mickael Perrin was working in the field of single molecular junctions (as PhD student in 2011-2015 and as a postdoctoral researcher in 2015-2016 at Delft Technical University in the group of Herre van der Zant).

Abstract

Organic electrochemical transistors (OECTs) are increasingly studied as transducers in sensing applications. While much emphasis has been placed on analyzing and maximizing the OECT signal, noise has been mostly ignored, although it determines the resolution of the sensor. The major contribution to the noise in sensing devices is the 1/f noise, dominant at low frequency. In this work, we demonstrate that the 1/f noise in OECTs follows a charge-noise model, which reveals that the noise is due to charge fuctuations in proximity or within the bulk of the channel material. We present the noise scaling behavior with gate voltage, channel dimensions and polymer thickness. Our results suggest the use of large area channels in order to maximize the signal-to-noise-ratio
(SNR) for biochemical and electrostatic sensing applications. Comparison with literature shows that the magnitude of the noise in OECTs is similar to that observed in graphene transistors, and only slightly higher compared to Carbon nanotubes and Silicon nanowire devices. In a model ion-sensing experiment with OECTs, we estimate crucial parameters such as the characteristic SNR and corresponding limit of detection.

Charge Noise in Organic Electrochemical Transistors
Ralph L. Stoop, Kishan Thodkar, Michele Sessolo and Henk Bolink, Christian Schonenberger and Michel Calame
to appear in Phys. Rev. Applied

On December 1st 2016, Oliver Braun joined our group as a PhD student under the joint supervision of Michel Calame and Prof. Dr. Ilaria Zardo (Uni Basel). Oliver will work on electronic transport and thermopower in nanoscale devices.