Abstract

Ultrathin 2D ferroelectrics with high Curie temperature are critical for multi-functional ferroelectric devices. However, the ferroelectric spontaneous polarization is consistently broken by the strong thermal fluctuations at high temperature, resulting in the rare discovery of high-temperature ferroelectricity in 2D materials. Here, we report a chemical vapor deposition (CVD) method to synthesize 2D CuCrSe2 nanosheets. The crystal structure is confirmed by scanning transmission electron microscopy (STEM) characterization. The measured ferroelectric phase transition temperature of ultrathin CuCrSe2 is about ∼ 800 K. Significantly, the switchable ferroelectric polarization is observed in ∼ 5.2 nm nanosheet. Moreover, the in-plane (IP) and out-of-plane (OOP) ferroelectric response are modulated by different maximum bias voltage. This work provides a new insight into the construction of 2D ferroelectrics with high Curie temperature.

https://doi.org/10.1002/adma.202400655