June-Mo Yang, Ju-Hee Lee, Young-Kwang Jung, So-Yeon Kim, Jeong-Hoon Kim, Seul-Gi Kim, Jeong-Hyeon Kim, Seunghwan Seo, Dong-Am Park, Jin-Wook Lee, Aron Walsh, Jin-Hong Park, Nam-Gyu Park
Advanced science (Weinheim, Baden-Wurttemberg, Germany) 2022 MayFor valence change memory (VCM)-type synapses, a large number of vacancies help to achieve very linearly changed dynamic range, and also, the low activation energy of vacancies enables low-voltage operation. However, a large number of vacancies increases the current of artificial synapses by acting like dopants, which aggravates low-energy operation and device scalability. Here, mixed-dimensional formamidinium bismuth iodides featuring in-situ formed type-I band structure are reported for the VCM-type synapse. As compared to the pure 2D and 0D phases, the mixed phase increases defect density, which induces a better dynamic range and higher linearity. In addition, the mixed phase decreases conductivity for non-paths despite a large number of defects providing lots of conducting paths. Thus, the mixed phase-based memristor devices exhibit excellent potentiation/depression characteristics with asymmetricity of 3.15, 500 conductance states, a dynamic range of 15, pico ampere-scale current level, and energy consumption per spike of 61.08 aJ. A convolutional neural network (CNN) simulation with the Canadian Institute for Advanced Research-10 (CIFAR-10) dataset is also performed, confirming a maximum recognition rate of approximately 87%. This study is expected to lay the groundwork for future research on organic bismuth halide-based memristor synapses usable for a neuromorphic computing system. © 2022 The Authors. Advanced Science published by Wiley-VCH GmbH.
June-Mo Yang, Ju-Hee Lee, Young-Kwang Jung, So-Yeon Kim, Jeong-Hoon Kim, Seul-Gi Kim, Jeong-Hyeon Kim, Seunghwan Seo, Dong-Am Park, Jin-Wook Lee, Aron Walsh, Jin-Hong Park, Nam-Gyu Park. Mixed-Dimensional Formamidinium Bismuth Iodides Featuring In-Situ Formed Type-I Band Structure for Convolution Neural Networks. Advanced science (Weinheim, Baden-Wurttemberg, Germany). 2022 May;9(14):e2200168
PMID: 35307991
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