Photo-Assisted Ferroelectric Domain Control for α-In 2 Se 3 Artificial Synapses Inspired by Spontaneous Internal Electric Fields

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 20; no. 22; p. e2307346
• Main Authors: Kang, Seok-Ju, Jung, Wonzee, Gwon, Oh Hun, Kim, Han Seul, Byun, Hye Ryung, Kim, Jong Yun, Jang, Seo Gyun, Shin, BeomKyu, Kwon, Ojun, Cho, Byungjin, Yim, Kanghoon, Yu, Young-Jun
• Format: Journal Article
• Language: English
• Published: Germany 01.05.2024
• Subjects: ferroelectric; 2D materials; built‐in electric field; artificial synapses; α‐In2Se3; Fermi level shift; polarization switching
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202307346

α-In Se semiconductor crystals realize artificial synapses by tuning in-plane and out-of-plane ferroelectricity with diverse avenues of electrical and optical pulses. While the electrically induced ferroelectricity of α-In Se shows synaptic memory operation, the optically assisted synaptic plasticity in α-In Se has also been preferred for polarization flipping enhancement. Here, the synaptic memory behavior of α-In Se is demonstrated by applying electrical gate voltages under white light. As a result, the induced internal electric field is identified at a polarization flipped conductance channel in α-In Se /hexagonal boron nitride (hBN) heterostructure ferroelectric field effect transistors (FeFETs) under white light and discuss the contribution of this built-in electric field on synapse characterization. The biased dipoles in α-In Se toward potentiation polarization direction by an enhanced internal built-in electric field under illumination of white light lead to improvement of linearity for long-term depression curves with proper electric spikes. Consequently, upon applying appropriate electric spikes to α-In Se /hBN FeFETs with illuminating white light, the recognition accuracy values significantly through the artificial learning simulation is elevated for discriminating hand-written digit number images.