Online PhD defence by Xiaojing Zhao: Gate Electrostatics in Narrow Graphene Devices

The defence will be carried out as an online video conference

Signing up as audience please contact Peter Bøggild:


Professor Peter Bøggild, DTU Physics


Assistant Professor José Caridad, DTU Physics

Evaluation Board

PD Dr. Thilo Glatzel, Department of Physics, University of Basel, Switzerland
Associate Professor Jakob Kjelstrup-Hansen, University of Southern Denmark, Denmark
Chairman: Professor Mads Brandbyge, DTU Fysik


Professor Antti-Pekka Jauho, DTU Physics


Graphene-based field effect transistors are widely used to investigate the electron transport in graphene and as components in their own right. Due to the low density of states and the specifics of the device geometry, the charge carrier density can have significant variations in the channel, which for graphene devices can have a great influence on the behavior, function and performance. Fringe fields at the graphene edges, the interplay between the gate, dielectric environment and graphene electronic system is complex, and gate electrostatics have turned out to be essential to understand. In this PhD project, the charge accumulation is visualised by Kelvin Probe Force Microscopy, and compared to simulations and analytical calculations. The dependence of the graphene channel width, edge disorder, substrate and measurement environment on the charge accumulation is investigated and discussed. Additionally, the local strain and doping of graphene bubbles in van der Waals heterostructures – junctions between dissimilar 2D materials held together by van der Waals forces – are analysed with confocal Raman microscopy.


Wed 22 Apr 20


DTU Fysik


Online Defence
Contact Peter Bøggild for participation