Two-dimensional (2D) ferroelectric materials, which possess electrically switchable spontaneous polarization and can be easily integrated with semiconductor technologies, is of utmost importance in the advancement of high-integration low-power nanoelectronics. Despite the experimental discovery of certain 2D ferroelectric materials such as CuInP₂S₆ and In₂Se₃, achieving stable ferroelectricity at room temperature in these materials continues to present a significant challenge. Herein, stable ferroelectric order at room temperature in the 2D limit is demonstrated in van der Waals SnP₂S₆ atom layers, which can be fabricated via mechanical exfoliation of bulk SnP₂S₆ crystals. Switchable polarization is observed in thin SnP₂S₆ of ∼7 nm. Importantly, a van der Waals ferroelectric field-effect transistor (Fe-FET) with ferroelectric SnP₂S₆ as top-gate insulator and p-type WTe_0.6Se_1.4 as the channel was designed and fabricated successfully, which exhibits a clear clockwise hysteresis loop in transfer characteristics, demonstrating ferroelectric properties of SnP₂S₆ atomic layers. In addition, a multilayer graphene/SnP₂S₆/multilayer graphene van der Waals vertical heterostructure phototransistor was also fabricated successfully, exhibiting improved optoelectronic performances with a responsivity (R) of 2.9 A/W and a detectivity (D) of 1.4 × 10¹² Jones. Our results show that SnP₂S₆ is a promising 2D ferroelectric material for ferroelectric-integrated low-power 2D devices.

二维（2D）铁电材料具有可电切换的自发极化，并且可以轻松与半导体技术集成，对于高集成低功率纳米电子学的发展至关重要。尽管实验发现了某些2D铁电材料，例如CuInP ₂ S ₆和In ₂ Se ₃，但在这些材料中在室温下实现稳定的铁电性仍然是一个重大挑战。在此，在范德华SnP ₂ S _{6原子层中证明了室温下二维极限下的稳定铁电有序，该原子层可以通过块状SnP 2} S ₆晶体的机械剥离来制造。在～7 nm 的薄 SnP ₂ S ₆中观察到可切换的偏振。重要的是，成功设计并制造了一种以铁电 SnP ₂ S ₆作为顶栅绝缘体、p 型 WTe _0.6 Se _1.4作为沟道的范德华铁电场效应晶体管（Fe-FET） ，该晶体管表现出明显的顺时针磁滞传输特性中的环路，展示了 SnP ₂ S ₆原子层的铁电特性。此外，还成功制备了多层石墨烯/SnP ₂ S ₆ /多层石墨烯范德华垂直异质结构光电晶体管，其光电性能得到改善，响应度（R）为2.9 A/W，探测灵敏度（D）为1.4 × 10 ¹²琼斯.我们的结果表明，SnP ₂ S ₆是一种有前途的用于铁电集成低功耗二维器件的二维铁电材料。