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Abstract The development of next‐generation in‐memory and neuromorphic computing can be realized with memory transistors based on 2D ferroelectric semiconductors. Among these, In2Se3is the interesting since it possesses ferroelectricity in 2D quintuple layers. Synthesis of large amounts of In2Se3crystals with the desired phase, however, has not been previously achieved. Here, the gram‐scale synthesis of α‐In2Se3crystals using a flash‐within‐flash Joule heating method is demonstrated. This approach allows the synthesis of single‐phase α‐In2Se3crystals regardless of the conductance of precursors in the inner tube and enables the synthesis of gram‐scale quantities of α‐In2Se3crystals. Then, α‐In2Se3flakes are fabricated and used as a 2D ferroelectric semiconductor FET artificial synaptic device platform. By modulating the degree of polarization in α‐In2Se3flakes according to the gate electrical pulses, these devices exhibit distinct essential synaptic behaviors. Their synaptic performance shows excellent and robust reliability under repeated electrical pulses. Finally, it is demonstrated that the synaptic devices achieve an estimated learning accuracy of up to ≈87% for Modified National Institute of Standards and Technology patterns in a single‐layer neural network system.
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3D Domain Arrangement in van der Waals Ferroelectric α‐In 2 Se 3
Abstract One of the exceptional features of the van der Waals (vdW) ferroelectrics is the existence of stable polarization at a level of atomically thin monolayers. This ability to withstand a detrimental effect of the depolarization fields gives rise to complex domain configurations characterized, among others, by the presence of layered “antipolar” head‐to‐head (H‐H) or tail‐to‐tail (T‐T) dipole arrangements. In this study, tomographic piezoresponse force microscopy (TPFM) is employed to study the 3D polarization arrangement in vdW ferroelectricα‐In2Se3. Sequential removal of thin layers from the polar surface using the PFM tip reveals a complex 3D profile of the domain walls in theα‐In2Se3crystals. Antiparallel domain layers stacked along the polar direction are also observed by PFM imaging of the non‐polar surfaces showing that H‐H and T‐T domain boundaries are commonly present inα‐In2Se3. Application of TPFM to the electrically written domains allows evaluation of their geometrical lateral‐to‐vertical size aspect ratio, which shows a strong prevalence for the sidewise expansion in comparison to the forward growth. LocalI–Vmeasurements reveal a strong polarization direction dependence of conductivity due to the modulation of the energy barrier height as corroborated by theoretical modeling.
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- PAR ID:
- 10527836
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Functional Materials
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/adfm.202403537
