Physical Vapor Deposition of Large-Area In ₂ Se ₃ Nanosheet-Derived Films for High-Density Nonvolatile Memory Devices

The polymorphism of two-dimensional (2D) In2Se3 holds significant potential for next-generation memory devices. However, the controllable, large-scale growth of uniform 2D In2Se3 films remains challenging. Herein, we report a modified space-confined physical vapor deposition (PVD) approach for the controlled layer-by-layer synthesis of centimeter-scale In2Se3 films. Transmission electron microscopy (TEM) and layer-dependent second-harmonic generation (SHG) mapping reveal a unique phase stratification within the films. The as-grown In2Se3 films display characteristic polarization-dependent charge transport and a switchable ferroelectric diode effect. Moreover, in Pt/In2Se3/Ag crossbar devices, we observe a distinct conductive filament-based resistive switching with an on/off ratio exceeding 1 × 104. Multiple nonvolatile conductance states are precisely modulated by varying the compliance current, enabling multilevel data storage. Finally, we demonstrate integrated arrays of In2Se3/MoS2 heterojunction field-effect transistors, which show a hysteresis window over 90 V with an on/off ratio exceeding 105 and uniform memory performance. This work provides a reliable pathway for synthesizing high-quality, large-area 2D ferroelectric films for advanced memory and neuromorphic computing applications.