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O: Fachverband Oberflächenphysik

O 65: Poster Wednesday: Surface Structure, Epitaxy and Growth

O 65.4: Poster

Mittwoch, 3. April 2019, 17:45–20:00, Poster B1

In-situ analysis of ultra-thin alkali metal films using optical transmission spectroscopy — •Hendrik Mathies Wrigge, Thomas Dziuba, Joerg Malindretos, Angela Rizzi, and Martin Wenderoth — IV. Physikalisches Institut, Georg August Universität Göttingen, Germany

Controlling the thickness of ultra-thin alkali metal films is a challenging task. Standard calibration techniques using e.g. ambient AFM, fail due to the high chemical reactivity of these metals. In this contribution, we present an alternative approach based on an in-situ optical transmission spectroscopy. Films are prepared by depositing pure alkalimetal from a dispenser on a glass substrate under UHV condition. While deposition, the optical transmission of the film is measured over a broad spectral range from 300 nm up to 1000 nm continuously (30 second per spectrum). We analyze distinct spectral features, which change according to the film thickness. Applying the scattering theory of non-spherical particle [1,2], the spectral features can be assigned to the film thickness and its nanoscopic structure. For comparison, we measured thin Ag films in the same setup. For Ag films, thickness as well as the structure is analyzed using AFM. In summary, our optical setup is able to measure deposition rate down to submonolayers per minute.

Work supported by DFG through SPP 1666

Reference: [1] K. Lance Kelly et al., J.Phys. Chem. B, 107, 668-677 (2003) [2] Luis J. Mendoza Herrera et al., Journal of Applied Physics 116, 233105 (2014)