Berlin 2018 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 55: Multiferroic Oxide Thin Films and Heterostructures I (joint session KFM/TT/MA)
TT 55.8: Vortrag
Mittwoch, 14. März 2018, 11:45–12:00, EMH 225
Domain Engineering of the Bulk Photovoltaic Effect in Bismuth Ferrite — •David Knoche1,2, Niranjan Ramakrishnegowda1,2, Yeseul Yun1,2, and Akash Bhatnagar1,2 — 1Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany — 2Zentrum für Innovationskompetenz SiLi-nano, Halle (Saale), Germany
The photovoltaic (PV) effect in multiferroic bismuth ferrite (BFO) can be largely attributed to the bulk photovoltaic (BPV) mechanism. The mechanism is associated to the absence of inversion symmetry in these materials. The principle of the BPV effect, that results in an above-bandgap open circuit voltage (Voc), differs from the well-known photovoltaic effect observed in semiconductors like silicon, and still demands in-depth analysis. In this regard, the contribution of ferroic aspects, such as orientation of domains, is crucial and can be potentially used as a tuning parameter.
Thin films of single crystalline BiFeO3 were grown epitaxially via pulsed laser deposition. Planar electrodes with different in-between distances were deposited on top of the sample. The domain orientations within the measurement gap were manipulated by applying high electric fields across the electrodes. Gradual increment in the applied electric field was crucial in obtaining intermediate domain architectures, that were visualized with piezo force microscope (PFM). Photoelectrical response was measured in conjunction to evaluate the influence on Voc and short circuit current.