Dissertation

Low-Energy Electron Microscopy on Two-Dimensional Systems: Growth, Potentiometry and Band Structure Mapping

Promotor: Prof.dr. J.M. van Ruitenbeek, Prof.dr. R.M. Tromp

Author

J. Kautz

Date

30 April 2015

Links

Thesis in Leiden Repository

Low Energy Electron Microscopy (LEEM) is a microscopy technique typically used to study surface processes. The sample is illuminated with a parallel beam of electrons under normal incidence and the reflected electrons are projected onto a pixelated detector, where an image is formed. In the first part of this thesis, we use LEEM to study the behavior of submonolayers of gold on Si(111). After a thorough analysis of the Si-Au system, we describe the behavior of these (sub)monolayers when exposed to alkanethiols. In the second part of this thesis we move away from pure surface physics and introduce two new applications for LEEM. The first of these, Low-Energy Electron Potentiometry (LEEP), can be used to visualize electrical conductance. We show that for layered two-dimensional materials we can obtain a higher resolution in LEEP experiments. Finally, in chapter 6, we present a new method to measure the dispersion relation of unoccupied states in two-dimensional layered materials.

• band structure
• electron microscopy
• potentiometry