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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 21: Crystallization, Nucleation and Self-Assembly

CPP 21.8: Vortrag

Montag, 16. März 2020, 16:45–17:00, ZEU 255

Vertically aligned silica in the hard X-ray spotlight: an in situ GISAXS study of EASA — •Gilles E. Moehl¹, Li Shao¹, Samuel S. Fitch¹, Chris Nicklin², Jonathan Rawle², Philip N. Bartlett¹, and Andrew L. Hector¹ — ¹Chemistry, University of Southampton, Southampton, SO17 1BJ, UK — ²Diamond Light Source, Didcot, OX11 0DE, UK

Under the Advanced Devices by Electroplating EPSRC programme grant (EP/N035437/1) we are working on the integration of nanowire semiconductor structures into electronics, by electrodepositing high quality chalcogenide semiconductors into aligned mesoporous templates. Mesoporous silica films are typically produced by evaporation-induced self assembly (EISA), but vertical alignment of the pores to the substrate is very difficult to achieve. Hexagonal arrays of vertically aligned mesopores can be achieved by electrochemically assisted surfactant assembly (EASA). The application of a negative potential to an electronically conductive substrate results in the self-assembly of a cationic surfactant (typically cetyltrimethylammonium bromide) close to the substrate surface, but also the formation of spheroidal surface aggregates, limiting the obtainable film thickness to a few hundreds of nm. The resulting pore spacing and diameter of only a few nanometres make the characterisation of such structures very challenging and time consuming. In this work, we show the results obtained from in situ GISAXS experiments done during the EASA of silica, following the evolution of the structure formation in real time with sub-second time resolution.