Low-Dose and Stable X-ray Detection Enabled by Ferroelectric Perovskite Oxides

Ferroelectric perovskites are recognized as promising candidates for use in optoelectronics due to the efficient electron and hole extraction enabled by the spontaneous electric polarization induced depolarization electric field. Ferroelectric perovskite oxides also show good stability in harsh chemical, mechanical, and thermal conditions and can be fabricated by using robust and scalable methods. However, the small photocurrent of the typical ferroelectric oxide optoelectronics greatly limits their applications, such as in photovoltaics and photocatalysis. Here, we show that ferroelectric perovskite oxides are suitable for low-dose X-ray detection (ultraweak radiation detection). Ferroelectric plate-like perovskite-type CaBi2Ta2O9 (CBTa), prepared by a solid-state sintered reaction method, displays a spontaneous polarization (Ps) of 6.5 μC cm–2, a remanent polarization (Pr) of 4.9 μC cm–2, and a high Curie temperature (Tc) of 1196 K. Large resistivity and high Pr of CBTa enable a good response to low-dose X-rays under zero bias, resulting in a detection limit of 30 nGyair s–1 for the detector, which is much lower than the requirement for X-ray diagnostics (5.5 μGyair s–1). The CBTa detectors also exhibit ultralow noise and good operation stability. This study will motivate new strategies to explore low-dose and stable X-ray detectors with ferroelectric oxides.