Ferroelectric ultraviolet photodetector material with ultrafast response speed.

Yan, Xuexi; Yan, Tingting; Li, Lingli; Cao, Yi; Wang, Xinwei; Wang, Jinghui; Tao, Ang; Yao, Tingting et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Ferroelectric films are promising to be used for high-performance photodetectors due to their intrinsic electric fields and high dielectric constants. However, the presence of high-density domains with varying polarization directions can severely degrade comprehensive performance. Here, we fabricate high-quality SrAl<sub>11-δ</sub>TiO<sub>19</sub> (SATO) ferroelectric films through a solid-state reaction. The SATO film possesses a magnetoplumbite-type structure with polarization along the c-axis and exhibits the possibility of single-domain ferroelectrics. Ferroelectric performance tests show that the remnant polarization of SATO film reaches 7.8 μC/cm<sup>2</sup> and the polarization retention exceeds 500 hours. Optoelectronic performance measurements reveal that the SATO photodetector exhibits excellent performance with response wavelength of 330 nm, responsivity of 860 mA/W, detectivity of 1.63 × 10<sup>13</sup> Jones, switching ratio of 1.9 × 10<sup>4</sup>, and ultrafast rise/fall response speed of 6.8 ns/17.7 ns (i.e., nearly 10000 times faster than traditional photodetectors). The outstanding properties highlight SATO as an outstanding candidate for next-generation photodetectors.