An all-two-dimensional Fe-FET retinomorphic sensor based on the novel gate dielectric In ₂ Se _{3− x} O _x

Two-dimensional (2D) ferroelectric field-effect transistors (Fe-FETs) have attracted extensive interest as a competitive platform for implementing future-generation functional electronics, including digital memory and brain-inspired computing circuits. In 2D Fe-FETs, the 2D ferroelectric materials are more suitable as gate dielectric materials compared to 3D ferroelectric materials. However, the current 2D ferroelectric materials (represented by α-In₂Se₃) need to be integrated with other 3D gate dielectric layers because of their high conductivity as a ferroelectric semiconductor. This 2D/3D hybrid structure can lead to compatibility problems in practical devices. In this study, a new 2D gate dielectric material that is compatible with the complementary metal-oxide semiconductor process was found by using oxygen plasma treatment. The 2D gate dielectric material obtained shows excellent performance, with an equivalent oxide thickness of less than 0.15 nm, and excellent insulation, with a leakage current of less than 2 × 10^-5 A cm^-2 (under a 1 V gate voltage). Based on this dielectric layer and the α-In₂Se₃ ferroelectric gate material, we fabricated an all-2D Fe-FET high-performance photodetector with a high on/off ratio (∼10⁵) and detectivity (>10¹³ Jones). Moreover, the photoelectric device integrates perception, memory and computing characteristics, indicating that it can be applied to an artificial neural network for visual recognition.