Berlin 2012 – scientific programme

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DS: Fachverband Dünne Schichten

DS 37: Poster II: Focused electron beam induced processing for the fabrication of nanostructures (focused session, jointly with O); Nanoengineered thin films; Layer properties: electrical, optical, and mechanical properties; Thin film characterization: structure analysis and composition (XRD, TEM, XPS, SIMS, RBS,..); Application of thin films

DS 37.6: Poster

Thursday, March 29, 2012, 15:00–17:00, Poster E

Work function measurements of sputtered TiO₂ in UHV ambience — •Sonja Urbahn, Rüdiger M. Schmidt, Alexandra Yatim, and Matthias Wuttig — I. Physikalisches Institut (IA) RWTH-Aachen University

Titanium Dioxide (TiO₂) is a material with unique properties which have led to various applications such as anti-reflective coatings or self-cleaning surfaces. In particular the latter is made possible by its outstanding photocatalytic activity. However, the underlying process behind this attractive feature is still sparsely investigated.

Thus it is the aim of the present work to correlate the structural features of reactively sputtered TiO₂ with its photocatalytic activity to be able to optimize future applications. Since self-cleaning implies the diffusion of photo generated charge carriers to the surface where they react with adsorbates, a change of the photocatalytic activity involves a change of the surface potential and thus of the work function. We show data measured with a Kelvin probe in UHV-ambience and link the characteristic behavior under UV illumination with structural properties and specific deposition parameters. Additionally we compare the UHV measurements with previously performed experiments in air to gain a deeper insight into the influence of different atmospheres. Our data contribute to the understanding of the photocalytic properties on a microscopic scale.