Master assignments

Noble metal patterns by controlled dewetting on 3D curved surfaces


Introduction

Deposition of well-dispersed noble metal particles is a key process in the production of supported catalysts. Our interest is to achieve patterns of such dispersed particles by de-wetting of an originally uniform thin metal coating. On substrates like monocrystalline silicon (100) wafers with an oxide layer, it has been demonstrated that it is possible to gain control over the dewetting process, and intricate patterns can be achieved  [1]. The experimental studies show that thin metal films can break down to single clusters upon annealing at temperatures below the melting point [2]. This results in various possibilities in the formation of ordered metal particles and self-aligned structures in mass production of MEMS devices, as well as in prototyping of plasmonic and catalytic structures [3].  

Assignment

The assignment focuses on the construction of various 3D test structures, with different convex and concave features of different sizes (ranging from nanometers to micrometers), as well as combinations thereof, with the goal of studying the effect of local 3D surface curvature on the dewetting process. The choice of structures will be based on theoretical considerations (including modeling, if required). Experimental work will consist of the application of silicon etching methods in combination with oxidation or thin film deposition processes to achieve the chosen test structures, with subsequent metal coating and annealing of the structure.

The project is dedicated practical and/or theoretical study to dewetting and particularly templated dewetting, and includes micromachining work in the NanoLab of MESA+. 

Background

The study would be most suitable for a Nanotechnology student, Chemical Engineering and Applied Physics students with an interest in surface energy-related processes are also invited.

 References

1. Giermann, A. L., & Thompson, C. V. (2005). Solid-state dewetting for ordered arrays of crystallographically oriented metal particles. Applied Physics Letters, 86(12), 1–3. https://doi.org/10.1063/1.1885180
2. Müller, C. M., & Spolenak, R. (2013). Dewetting of Au and AuPt alloy films: A dewetting zone model. Journal of Applied Physics, 94301(9), 1–14. https://doi.org/10.1063/1.4794028 
3. Altomare, M., Nguyen, N. T., & Schmuki, P. (2016). Templated dewetting: designing entirely self-organized platforms for photocatalysis. Chemical Science, 7(12), 6865–6886. https://doi.org/10.1039/C6SC02555B

Contacts

Vlad Tkachuk v.tkachuk
Han Gardeniers
 j.g.e.gardeniers