The development and application of artificial intelligence have led to the exploitation of low‐power and compact intelligent information‐processing systems integrated with sensing, memory, and neuromorphic computing functions. The 2D van der Waals (vdW) materials with abundant reservoirs for arbitrary stacking based on functions and enabling continued device downscaling offer an attractive alternative for continuously promoting artificial intelligence. In this study, full 2D SnS₂/h‐BN/CuInP₂S₆ (CIPS)‐based ferroelectric field‐effect transistors (Fe‐FETs) and utilized light‐induced ferroelectric polarization reversal to achieve excellent memory properties and multi‐functional sensing‐memory‐computing vision simulations are designed. The device exhibits a high on/off current ratio of over 10⁵, long retention time (>10⁴ s), stable cyclic endurance (>350 cycles), and 128 multilevel current states (7‐bit). In addition, fundamental synaptic plasticity characteristics are emulated including paired‐pulse facilitation (PPF), short‐term plasticity (STP), long‐term plasticity (LTP), long‐term potentiation, and long‐term depression. A ferroelectric optoelectronic reservoir computing system for the Modified National Institute of Standards and Technology (MNIST) handwritten digital recognition achieved a high accuracy of 93.62%. Furthermore, retina‐like light adaptation and Pavlovian conditioning are successfully mimicked. These results provide a strategy for developing a multilevel memory and novel neuromorphic vision systems with integrated sensing‐memory‐processing.

Layer-dependent ferroelectric polarization in 2H-stacked α-In ₂ Se ₃ attributed to a 180 degree in-plane rotation in the adjacent layers is reported.

Two-dimensional (2D) van der Waals (vdW) magnetic materials with reduced dimensionality often exhibit unexpected properties compared to their bulk counterparts. In particular, the mechanical flexibility of 2D structure, enhanced ferromagnetism at reduced layer thickness, as well as robust perpendicular magnetic anisotropy are quite appealing for constructing novel spintronic devices. The vdW vanadium diselenide (VSe₂) is an attractive material whose bulk is paramagnetic while monolayer is ferromagnetic with a Curie temperature (T_c) above room temperature. To explore its possible device applications, a detailed investigation on the thickness-dependent magnetism and strain modulation behavior of VSe₂ is highly demanded. In this article, the VSe₂ nanoflakes were controllably prepared via chemical vapor deposition (CVD) method. The few-layer single VSe₂ nanoflakes were found to exhibit magnetic domain structures at room temperature. Ambient magnetic force microscopy (MFM) phase images reveal a clear thickness-dependent magnetism and the MFM phase contrast is traceable for the nanoflakes of layer thickness below ∼ 6 nm. Moreover, applying strain is found efficient in modulating the magnetic moment and coercive field of 2D VSe₂ at room temperature. These results are helpful for understanding the ferromagnetism of high temperature 2D magnets and for constructing novel straintronic devices or flexible spintronic devices.

Sliding ferroelectric semiconductors can advance the applications of slidetronics in silicon-compatible microelectronic and optoelectronic devices for the post-Moore era. However, traditional sliding ferroelectrics typically require complex artificial stacking to break symmetry, and most of them lack atomic-scale evidence. Here, we report a sliding ferroelectric semiconductor of naturally parallel-stacked ReSe₂ with layer number N ≥ 3 through rational sliding approach, which is different from the reported sliding ferroelectrics with N ≥ 2. This sliding ferroelectricity avoids the rigorous artificially stacking design. The origin of ferroelectricity arises from the fact that the sliding of arbitrary middle atomic layer breaks the spatial inversion symmetry. We also directly measure the polarization value of ReSe₂ by polarization-electric field hysteresis. Additionally, the electro-tunable ferroelectric polarization is further confirmed by microscopic ferroelectric switching. And, the sliding ferroelectricity enables switchable ferroelectric diode and programmable photovoltaic effect. Our study sheds light on the exploration of sliding ferroelectric semiconductors in naturally parallel-stacked configurations.