Strongly enhanced and tunable photovoltaic effect in ferroelectric-paraelectric superlattices.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 34078597.
- Also identified by DOI 10.1126/sciadv.abe4206 and PMC identifier 8172128.
- Licence recorded as CC BY-NC.
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Abstract
Ever since the first observation of a photovoltaic effect in ferroelectric BaTiO<sub>3</sub>, studies have been devoted to analyze this effect, but only a few attempted to engineer an enhancement. In conjunction, the steep progress in thin-film fabrication has opened up a plethora of previously unexplored avenues to tune and enhance material properties via growth in the form of superlattices. In this work, we present a strategy wherein sandwiching a ferroelectric BaTiO<sub>3</sub> in between paraelectric SrTiO<sub>3</sub> and CaTiO<sub>3</sub> in a superlattice form results in a strong and tunable enhancement in photocurrent. Comparison with BaTiO<sub>3</sub> of similar thickness shows the photocurrent in the superlattice is 10<sup>3</sup> times higher, despite a nearly two-thirds reduction in the volume of BaTiO<sub>3</sub> The enhancement can be tuned by the periodicity of the superlattice, and persists under 1.5 AM irradiation. Systematic investigations highlight the critical role of large dielectric permittivity and lowered bandgap.