Research On Tunable Optpelectronic Devices Based On Two-Dimensional Ferroelectric Semiconductor α-In₂Se₃

As Moore’s Law continues to advance,the conventional silicon-based processes have faced significant challenges in terms of size reduction.Consequently,alternative materials must be explored to tackle these issues.Two-dimensional（2D）materials have garnered significant interest owing to their distinctive crystal structure,exceptional physical and chemical properties,including their ultrathin thickness,vast specific surface area,adjustable bandgap,and smooth surface.Two-dimensional ferroelectric materials have ferroelectricity and semiconductor properties,good scaling ability,and high carrier concentration,and thus have broad application prospects in micro-nano electronics and optoelectronics.Devices based on two-dimensional materials come in various types,such as photodetection,field-effect transistors,memory devices,and neuromorphic computing devices.This paper focuses on the construction and optoelectronic performance research of devices based on two-dimensional ferroelectric materials,including material synthesis,heterojunction device fabrication,optoelectronic detection performance testing of devices,and applications in optoelectronic memory.The main research content and conclusions are as follows:（1）Firstly,a new two-dimensional layered perovskite material was prepared by solution method.A Mo Te₂/（C₄H₉NH₃）₂（CH₃NH₃）₂Pb₃I₁₀/α-In₂Se₃ ferroelectric p-i-n van der Waals heterojunction was constructed,exhibiting significant photovoltaic effect.The all-dry transfer method was used in an inert environment to ensure the stability and high interface quality of the materials.The introduction of two-dimensional perovskite increased the short-circuit current density of the device by three orders of magnitude,making the device a sensitive self-powered photodetector with an on-off ratio of 2.4×10⁵,a detectivity of 1.2×10¹² Jones,and a response time of 730μs/620μs.In addition,the internal electric field was enhanced by programming the ferroelectric polarization ofα-In₂Se₃,which allowed the short-circuit current density to be controlled and increased by more than 25 times.Our research shows that high-performance optoelectronic devices based on two-dimensional ferroelectric van der Waals p-i-n heterojunctions have potential applications.（2）Due to the limitation of the bandgap,the response band ofα-In₂Se₃ is only in the visible light range.In order to enable it to respond to infrared light,a narrow bandgap material needs to be introduced.High-quality tellurium nanosheets were prepared by chemical vapor deposition,and a Te/α-In₂Se₃ heterojunction was used to demonstrate high-performance near-infrared optoelectronic memory.The ferroelectric polarization ofα-In₂Se₃ can be switched to a low-resistance state by photo-generated carriers migrating from the Te near-infrared light absorber,and it exhibits a high resistance state with a positive gate voltage.Therefore,this device can serve as a high-performance near-infrared photodetector with good responses at1550 nm and 1940 nm.In addition,the device can be used as a stable and multi-non-volatile resistance state element.Using this device,artificial neural networks with high recognition accuracy of 100%and 89.9%were implemented to identify a database of 64-pixel letters with 10%and 70%noise levels,providing a feasible approach for developing neural network architectures suitable for the infrared range.