Ferroelectric‐Controllable Optoelectronic Performance in 2D‐Metallic SnSe/Sc_0.25Al_0.75N Heterostructure

Abstract Scandium‐doped aluminium nitride (Sc_xAl_1‐xN)has made extensive progress in its applicationfor non‐volatile ferroelectric field effect transistors (FeFETs). However, ScAlN FeFET studies have mainly focused on memory devices based on n‐ and p‐type channel. Photodetectors based on ScAlN ferroelectric gatehave rarely been reported. Here, a FeFET device consisting of a metallic channel material, SnSe, and a ferroelectric gate material, Sc_0.25Al_0.75N is presented. Due to the different energy levels of Sc_0.25Al_0.75N and SnSe, a potential barrier is formed at the interface between them, which regulates the dark current and photoresponsivity of the heterostructure; meanwhile, the interfacial potential barrier is changed under three polarization states of Sc_0.25Al_0.75N. As a result, dark current of the device with Sc_0.25Al_0.75N gate is reduced by 10⁴, on/off ratio is increased by 40 times, and the photoresponsivity is enhanced to 1 × 10⁴ A W⁻¹ compared with that of SiO₂ gate; Moreover, on/off ratio of the devicesunder the positively polarized state is increased by nearly 10³ underillumination; under the negatively polarized state, photoresponsivity reaches 5.4 × 10⁵ and 3.1 × 10⁴ A W⁻¹ under illumination. This work demonstrates the feasibility of Sc_0.25Al_0.75N applied in FeFET photodetectors and opens up the possibility of developing ScAlN‐based optoelectronic devices.