Chemical Vapor Deposition Synthesis of Intrinsic High-temperature Ferroelectric 2D CuCrSe 2 .

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 CuCrSe 2 nanosheets. The crystal structure is confirmed by scanning transmission electron microscopy (STEM) characterization. The measured ferroelectric phase transition temperature of ultrathin CuCrSe 2 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. This article is protected by copyright. All rights reserved.