Berlin 2018 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 31: Poster Session II

DS 31.14: Poster

Donnerstag, 15. März 2018, 11:15–13:15, Poster F

Interface tuning by metallic and insulting interlayers in manganite-titanite heterojunctions — •Stephan Melles, Birte Kressdorf, Joerg Hoffmann, Ulrich Ross, and Christian Jooss — University of Goettingen, Institute of Materials Physics, Friedrich-Hund-Platz 1, 37077 Goettingen, Germany

New photovoltaic materials like complex oxides allow for fundamental studies of new conversion mechanisms which have the potential to overcome current efficiency limitations. Their interfaces play a crucial role in controlling charge transfer and charge separation, and determine the current-voltage (I−V) characteristics of such systems. Here, we present studies on interface design of manganite-titanite heterojunctions which are prepared by ion beam sputtering of thin films of hole doped Pr_0,66Ca_0,34MnO₃ (PCMO) on electron doped single crystalline SrTi_0.9975Nb_0.0025O₃ (STNO) substrates. The junction displays a rectifying I−V characteristic and a pronounced photovoltaic effect, involving polaronic excitations [1]. Preliminary results show that the sputter deposition of Cr interlayers can either modify the junction to an ohmic contact or modify the rectifying characteristic and enhance the photovoltaic effect, depending on thickness and preparation conditions. Consequently, we started to prepare wedge-shaped Cr interlayers, allowing for a systematic thickness dependent analysis. The growth mode of Cr layers is investigated by SEM and AFM studies and the change of cross plane current voltage characteristics is studied. The interfaces are characterized by transmission electron microscopy. Reference: [1] B. Ifland et al., New J. Phys. 19 (2017) 063046