Increasing bulk photovoltaic current by strain tuning

• Published in: Science advances Vol. 5; no. 3; p. eaau9199
• Main Authors: Nadupalli, Shankari, Kreisel, Jens, Granzow, Torsten
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01.03.2019
• Subjects: Applied Sciences and Engineering; SciAdv r-articles
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aau9199

Photovoltaic phenomena are widely exploited not only for primary energy generation but also in photocatalytic, photoelectrochemistry, or optoelectronic applications. In contrast to the interface-based photovoltaic effect of semiconductors, the anomalous or bulk photovoltaic effect in ferroelectrics is not bound by the Shockley-Queisser limit and, thus, can potentially reach high efficiencies. Here, we observe in the example of an Fe-doped LiNbO bulk single crystal the existence of a purely intrinsic "piezophotovoltaic" effect that leads to a linear increase in photovoltaic current density. The increase reaches 75% under a low uniaxial compressive stress of 10 MPa, corresponding to a strain of only 0.005%. The physical origin and symmetry properties of the effect are investigated, and its potential for strain-tuned efficiency increase in nonconventional photovoltaic materials is presented.