Seminar shows many opportunities for surface analysis

Published on
February 13, 2018

During the seminar on January 25th, hosted by Shared Research Facilities, the presentations highlighted different techniques and technologies available at Wageningen Campus to get more insight on surfaces. Each of the technologies and facilities offers a different piece of the puzzle into the surface composition.

The welcome and introduction to Shared Research Facilities of the first seminar in 2018 was done by Edda Neuteboom. To complement the technologies and facilities, she paid special attention to the newly acquired tribometer, which can offer another piece of the puzzle of surfaces as it measures friction and friction force between two surfaces. This technology is expected to feature in a seminar later this year.

The first presentation by Marcel Giesbers from the Wageningen Microscopy Centre offered an insight into possibilities of the Scanning Electron Microscope (SEM) for surface analysis. A technique in which an electron beam scans a sample in a raster pattern. With this technology qualitative and quantitative information is given about atomic elements on the surface through backscattered electron imaging and secondary electron imaging. Intensity map images of the surface can be built with a resolution of 0.8-0.9 nanometer. The thickness of a thin film layer can be characterised by Energy Dispersive X-ray spectrometry (EDX/ EDS) of a surface or of a cross section of the sample.

Han Zuilhof, chair of the Organic Chemistry group at Wageningen University, followed with his presentation of the Scanning Auger Microscope with a sampling depth to 3 nm with which the elemental composition of the surface can be obtained using the Auger effect of atoms. Information of the top (few) monolayers of the surface is gathered with a resolution of 10 nm. X-ray Photoelectron Spectroscopy (XPS) offers a more detailed chemical state of the surface compared with Auger or SEM, but at a lower spatial resolution.

Wout Knoben of the Wageningen Campus-based company Surfix, working on nanocoatings, shed light on the opportunities of the recently acquired Imaging Ellipsometer for surface analysis. This forms an image by measuring the change in polarisation of a light beam upon reflecting off the surface of thin films. As reflection is at the heart of this technique it is not suitable for all materials. It can be used to characterize film properties such as thickness, composition, roughness and porosity at ambient conditions, and can be used on both solid and liquid interfaces. For this technique information of layer structure and optical properties of the sample are needed as input for accurate modelling. This Shared Research Facility is located at the Surfix premises in PlusUltra.