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Abstract This work characterizes the structural, magnetic, and ferroelectric properties of epitaxial LuFeO3orthoferrite thin films with different Lu/Fe ratios. LuFeO3thin films are grown by pulsed laser deposition on SrTiO3substrates with Lu/Fe ratio ranging from 0.6 to 1.5. LuFeO3is antiferromagnetic with a weak canted moment perpendicular to the film plane. Piezoresponse force microscopy imaging and switching spectroscopy reveal room temperature ferroelectricity in Lu‐rich and Fe‐rich films, whereas the stoichiometric film shows little polarization. Ferroelectricity in Lu‐rich films is present for a range of deposition conditions and crystallographic orientations. Positive‐up‐negative‐down ferroelectric measurements on a Lu‐rich film yield ≈13 µC cm−2of switchable polarization, although the film also shows electrical leakage. The ferroelectric response is attributed to antisite defects analogous to that of Y‐rich YFeO3, yielding multiferroicity via defect engineering in a rare earth orthoferrite.
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Ultrahigh Bulk Photovoltaic Effect Responsivity in Thin Films: Unexpected Behavior in a Classic Ferroelectric Material
The bulk photovoltaic effect (BPE) has drawn considerable attention due to its ability to generate photovoltages above the bandgap and reports of highly enhanced photovoltaic current when using nanoscale absorbers or nanoscale electrodes, which, however, do not lend themselves to practical, scalable implementation. Herein, it is shown that a strikingly high BPE photoresponse can be achieved in an ordinary thin‐film configuration merely by tuning fundamental ferroelectric properties. Nonmonotonic dependence of the responsivity (RSC) on the ferroelectric polarization is observed and at the optimal value of the film polarization, a more than three orders of magnitude increase in theRSCfrom the bulk BaTiO3value is obtained, reachingRSCclose to 10−2 A W−1, the highest value reported to date for the archetypical ferroelectric BaTiO3films. Results challenge the applicability of standard first‐principles‐based descriptions of BPE to thin films and the inherent weakness of BPE in ferroelectric thin films.
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- Award ID(s):
- 2102895
- PAR ID:
- 10514989
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Solar RRL
- Volume:
- 7
- Issue:
- 23
- ISSN:
- 2367-198X
- Subject(s) / Keyword(s):
- ferroelectric bulk photovoltaic effect BSTO
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1002/solr.202300294
