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Percolation threshold enables optical resistive‐memory switching and light‐tuneable synaptic learning in segregated nanocomposites

Jaafar, Ayoub H.; O'Neill, Mary; Kelly, Stephen M.; Verrelli, Emanuele; Kemp, Neil T.

Authors

Ayoub H. Jaafar

Mary O'Neill



Abstract

An optical memristor where the electrical resistance memory depends on the history of both the current flowing through the device and the irradiance of incident light onto it is demonstrated. It is based on a nanocomposite consisting of functionalized gold nanoparticles in an optically active azobenzene polymer matrix. The composite has an extremely low percolation threshold of 0.04% by volume for conductivity because of the aggregation of the conducting nanoparticles into filamentary nanochannels. Optical irradiation results in photomechanical switching through expansion of the thin film from above to below the percolation threshold, giving a large LOW/HIGH resistance ratio of 103. The device acts as an artificial synapse, the conductivity or plasticity of which can be independently modulated, either electrically or optically, to enable tunable and reconfigurable synaptic circuits for brain‐inspired artificial intelligent or visual memory arrays. The lifetime of the resistive‐memory states is also optically controllable, which enables spatial modulation of long‐ and short‐term memory.

Journal Article Type Article
Publication Date Jul 1, 2019
Journal Advanced Electronic Materials
Print ISSN 2199-160X
Electronic ISSN 2199-160X
Publisher Wiley
Peer Reviewed Peer Reviewed
Volume 5
Issue 7
Article Number 1900197
Institution Citation Jaafar, A. H., O'Neill, M., Kelly, S. M., Verrelli, E., & Kemp, N. T. (2019). Percolation threshold enables optical resistive‐memory switching and light‐tuneable synaptic learning in segregated nanocomposites. Advanced Electronic Materials, 5(7), https://doi.org/10.1002/aelm.201900197
DOI https://doi.org/10.1002/aelm.201900197
Keywords Electronic, Optical and Magnetic Materials
Publisher URL https://onlinelibrary.wiley.com/doi/abs/10.1002/aelm.201900197