Regensburg 2013 – scientific programme

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DS: Fachverband Dünne Schichten

DS 32: Poster Session IV: Atomic layer deposition; Organic thin films; Organic Electronics and Phototovoltaics; Organic Materials for Spintronics - from spinterface to devices; Thin film photovoltaic materials and solar cells

DS 32.4: Poster

Thursday, March 14, 2013, 17:00–20:00, Poster B2

Atomic layer epitaxy of Ruddlesden-Popper film structures prepared by MAD — •Felix Massel, Sebastian Hühn, Markus Jungbauer, Markus Michelmann, Camillo Ballani, and Vasily Moshnyaga — I. Physikalisches Institut, Georg-August Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

Ruddlesden-Popper (RP) phases can be described by the general formula A_n−1A′₂ B_nO_3n+1, where A, A’, and B are cations, O is oxygen, and n is the number of the layers of octahedra in the perovskite-like stack. When aiming at high values of n, conventional solid state synthesis produces mixtures of phases with different n and the parent perovskite rather than pure phases. Submonolayer deposition precision is a way to successfully grow single phase RP films. RP films were prepared by vacuum free metalorganic aerosol deposition (MAD), which has several advantages over physical deposition methods, especially a high oxygen pressure of p(O₂) ≈ 0.2 bar. The films were prepared by controllable pulsed spray injections of A and B type precursor solutions into the MAD chamber. By means of optical ellipsometry, a layer-by-layer - i. e. A-O/B-O₂ - deposition was monitored in situ, giving early information on the film composition. Thin films of the Sr_n+1Ti_n O_3n+1 RP series were prepared for n = 1,,4. Further analysis of the films’ structure and morphology was done by XRD and AFM. In order to achieve single phase RP samples, a fine tuning of precursor volumes, deposition temperature, deposition rate, and pulse delay time was found to be crucial for a successful synthesis. This work was supported by IFOX of the European Community’s 7th Framework Programme.