E-guest Lecture : Viera Skakalova

Winding road to graphene

28.05.2020 - 28.05.2020

Viera Skakalova, professeure en Physique des matériaux nanostructurés à l'Université de Vienne, est actuellement fellow-in-residence à CY|AS, invitée du laboratoire LPMS

Two-dimensional graphene was isolated more than 10 years after discovery of one-dimensional carbon nanotubes - tubes made of graphene, and after zero-dimensional fullerene – balls rolled of graphene. We will present overview of its discovery, surprising properties and following hope that graphene will open the gate to a new technological platform for electronics, energy storage, mechanical support as well as ideally tight packaging.

We will also present our experimental results of the temperature dependence G(T) of electrical conductivity in monolayer graphene designed in the field effect transistor (FET) configuration. Instability and changes in the dependence G(T) during the heating-cooling cycles are found to be related to the mesoscopic conductance fluctuations, typically present in 2-dimensional systems. We found that, differently from other 2-dimensional systems, the phase coherence of electronic waves persists above 50 K. This is the cause of conductance fluctuations and it explains why significant changes of the G(T), either an increase or a decrease, in this low temperature range, are observed. At higher temperatures, molecules adsorbed on the graphene surface redistribute and cause the conductance variation at temperature cycling.

We performed transconductance measurements in magnetic field which enabled to identify Fractional Quantum Hall Effect (F-QHE) states for single layer and bilayer graphene devices. QHE in graphene can be observed at magnetic fields lower than 1T and shows unusual features.

At the end we will discuss problems standing in the way to production of graphene and its numerous applications.

Télécharger son CV

Date : jeudi 28 mai 2020 de 16h00 à 17h00

La vidéo est en ligne sur la chaîne YouTube de CY|AS.