After spending a week at EMPA in Zurich, Switzerland, depositing high quality TiW thin films in February, Curran, Nathalie and Anna travelled to DESY, Hamburg, Germany, in the first week of March to collect HAXPES data on them. We were back at one of our favourite HAXPES beamlines, P22 at PETRA III, and the work was, as always, expertly supported by the local team of Dr Christoph Schlueter and Dr Andrei Hloskovsky.
In order to ensure that the samples where in the best possible condition for measurement we needed to apply quite an involved level of logistics including vacuum sealing, glove box transferring, and in-situ sputtering. This enabled us to measure the films in their truly metallic state without interference from surface oxidation and contamination. Although HAXPES enables to probe the bulk of a sample, overlying surface oxides can significantly influence and perturb the HAXPES spectral quality. We both explored the influence of Ti/W composition on the electronic structure as well as a challenging experiment to try and probe the buried interface between TiW and the underlying SiO2/Si substructure. We also had time to explore the local offerings of cake and caffeinated beverages.
In the second half of February Curran and Anna spent a week at EMPA, the Swiss Federal Laboratories for Materials Science and Technology, in Zurich, Switzerland, to deposit a range of TiW films for an upcoming HAXPES experiment at DESY, Hamburg, Germany. The samples will be used to increase our understanding of mixed metal barrier materials for power electronics.
This collaboration was made possible by the award of a UCL Global Engagement Fund (GEF), a funding route available to UCL academics that supports collaboration with colleagues based in other countries.
Our colleagues at EMPA, Dr Sebastian Siol and Dr Siarhei Zhuk were excellent hosts and shared their extensive knowledge on the deposition of such metal systems. In parallel, Curran was able to immediately characterise all deposited samples using a combination of X-ray fluorescence (XRF), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). This provided a solid characterisation basis to finetune deposition parameters and achieve a high level of control over film thicknesses and composition.
Although it was an intense week of work, there was still time to enjoy the finer side of life in Zurich, including sampling some local delicacies including Schnitzel (pictured below), Raclette and a very good amount of Swiss chocolate.