Heterogeneous reservoir computing in second-order Ta2O5/HfO2 memristors

Nestor Ghenzi; Tae Won Park; Seung Soo Kim; Hae Jin Kim; Yoon Ho Jang; Kyung Seok Woo; Cheol Seong Hwang

doi:10.1039/D3NH00493G

Heterogeneous reservoir computing in second-order Ta₂O₅/HfO₂ memristors†

Nestor Ghenzi,

‡^ab Tae Won Park,‡^a Seung Soo Kim,^a Hae Jin Kim,^c Yoon Ho Jang,^a Kyung Seok Woo

*^a and Cheol Seong Hwang

*^a

Author affiliations

* Corresponding authors

^a Department of Materials Science and Engineering and Inter-University Semiconductor Research Center, Seoul National University Gwanak-ro 1, Gwanak-gu, Seoul 08826, Republic of Korea
E-mail: kevinwoo@snu.ac.kr, cheolsh@snu.ac.kr

^b Universidad de Avellaneda UNDAV and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina

^c Department of Materials Science and Engineering, Myongji University, Yongin 17058, Korea

Abstract

Multiple switching modes in a Ta₂O₅/HfO₂ memristor are studied experimentally and numerically through a reservoir computing (RC) simulation to reveal the importance of nonlinearity and heterogeneity in the RC framework. Unlike most studies, where homogeneous reservoirs are used, heterogeneity is introduced by combining different behaviors of the memristor units. The chosen memristor for the reservoir units is based on a Ta₂O₅/HfO₂ bilayer, in which the conductances of the Ta₂O₅ and HfO₂ layers are controlled by the oxygen vacancies and deep/shallow traps, respectively, providing both volatile and non-volatile resistive switching modes. These several control parameters make the second-order Ta₂O₅/HfO₂ memristor system present different behaviors in agreement with its history-dependent conductance and allow the fine-tuning of the behavior of each reservoir unit. The heterogeneity in the reservoir units improves the pattern recognition performance in the heterogeneous memristor RC system with a similar physical structure.

This article is part of the themed collection: Memristors and Neuromorphic Systems

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Article information

DOI: https://doi.org/10.1039/D3NH00493G
Article type: Communication
Submitted: 07 Nov 2023
Accepted: 06 Dec 2023
First published: 07 Dec 2023

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Nanoscale Horiz., 2024,9, 427-437

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Heterogeneous reservoir computing in second-order Ta₂O₅/HfO₂ memristors

N. Ghenzi, T. W. Park, S. S. Kim, H. J. Kim, Y. H. Jang, K. S. Woo and C. S. Hwang, Nanoscale Horiz., 2024, 9, 427 DOI: 10.1039/D3NH00493G

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