Two‐dimensional In₂Se₃: A rising advanced material for ferroelectric data storage

Abstract

Ferroelectric memory is a promising candidate for next‐generation nonvolatile memory owing to its outstanding performance such as low power consumption, fast speed, and high endurance. However, the ferroelectricity of conventional ferroelectric materials will be eliminated by the depolarization field when the size drops to the nanometer scale. As a result, the miniaturization of ferroelectric devices was hindered, which makes ferroelectric memory unable to keep up with the development of integrated‐circuit (IC) miniaturization. Recently, a two‐dimensional (2D) In2Se3 was reported to maintain stable ferroelectricity at the ultrathin scale, which is expected to break through the bottleneck of miniaturization. Soon, devices based on 2D In2Se3, including the ferroelectric field‐effect transistor, ferroelectric channel transistor, synaptic ferroelectric semiconductor junction, and ferroelectric memristor were demonstrated. However, a comprehensive understanding of the structures and the ferroelectric‐switching mechanism of 2D In2Se3 is still lacking. Here, the atomic structures of different phases, the dynamic mechanism of ferroelectric switching, and the performance/functions of the latest devices of 2D In2Se3 are reviewed. Furthermore, the correlations among the structures, the properties, and the device performance are analyzed. Finally, several crucial problems or challenges and possible research directions are put forward. We hope that this review paper can provide timely knowledge and help for the research community to develop 2D In2Se3 based ferroelectric memory and computing technology for practical industrial applications.

Bidirectional Synaptic Phototransistor Based on Two-Dimensional Ferroelectric Semiconductor for Mixed Color Pattern Recognition

“…The emerging 2D ferroelectric semiconductor α-In 2 Se 3 , with coupled ferroelectric and semiconductor characteristics as well as the electrically configurable interlocked out-of-plane (OOP) and in-plane (IP) polarization switching properties, is promising for neuromorphic computing applications. − Each monolayer α-In 2 Se 3 is arranged in the order of Se-In-Se-In-Se; the movement of central Se atom can reverse the orientation of the crystal structure of α-In 2 Se 3 , causing the lock-in polarization of OOP and IP, and lead to the robust existence of intrinsic ferroelectricity (Figure a, left panel). , We employed α-In 2 Se 3 as the channel material, a heavily boron-doped Si substrate as the back-gate electrode, Al 2 O 3 as the gate dielectric, and Cr/Au as source/drain electrodes (Figure a, right panel). The high quality of the exfoliated and transferred 2H α-In 2 Se 3 in the fabricated devices was demonstrated by Raman spectroscopy and X-ray diffraction (XRD) characterization (Figure S1).…”

Thermally Tunable Analog Memristive Behaviors in Sulfurized In2Se3 Nanoflakes for Bio-Plausible Synaptic Devices

“…Very recently, 2D/CMOS hybrid microchips with high-integration-density are fabricated and present computing-in-memory ability, representing a significant advance toward 2D neuromorphic applications . Similar to traditional materials-based nonvolatile memory technologies, 2D memristors with various memristive mechanisms have also been developed, such as resistive random-access memory, magneto-resistive random-access memory, ferroelectric random-access memory, phase change memory, etc. , …”

“…10 Similar to traditional materials-based nonvolatile memory technologies, 2D memristors with various memristive mechanisms have also been developed, such as resistive random-access memory, magneto-resistive random-access memory, ferroelectric random-access memory, phase change memory, etc. 11,12 Among many candidates for 2D memristors, α-In 2 Se 3 exhibits many advantages, such as high curie temperature (∼700 K), and photoelectric responsivity. 12,13 Leveraging on these merits, neuromorphic devices constructed by In 2 Se 3 memristors have been actively explored for implementation in neuromorphic computing.…”

“…Among many candidates for 2D memristors, α-In 2 Se 3 exhibits many advantages, such as high curie temperature (∼700 K), and photoelectric responsivity. , Leveraging on these merits, neuromorphic devices constructed by In 2 Se 3 memristors have been actively explored for implementation in neuromorphic computing. − Generally speaking, digital switching resulting from polarization flip in α-In 2 Se 3 facilitates information storage but does not faithfully mimic the synaptic plasticity . Moreover, to eventually realize brain-like information processing capability, achieving analog memristive behaviors and weight updates with a wide dynamic range is critical .…”

Bend-Induced Ferroelectric Domain Walls in α-In2Se3

“…Here, we investigate the impact of nanoscale bending in α-In 2 Se 3 , a room-temperature van der Waals ferroelectric with a thickness-dependent Curie temperature of 533–700 K. − α-In 2 Se 3 has been used in field-effect transistors, memristors, neural computing, and nonvolatile memories . Moreover, α-In 2 Se 3 exhibits rich electromechanical behavior, such as strain-induced phase changes and flexoelectric effects .…”