Percolation Threshold Enables Optical Resistive‐Memory Switching and Light‐Tuneable Synaptic Learning in Segregated Nanocomposites

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 10 3 . 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.

Plasmonic Optoelectronic Memristor Enabling Fully Light‐Modulated Synaptic Plasticity for Neuromorphic Vision

“…[10,17,19,[23][24][25][26] However, the reversible synaptic modulation (depression or potentiation) behavior of these materials must be controlled using electrical stimulation, which generates complex operations involving hybrid optical/electrical signals. [23,[25][26][27] To date, very few works have demonstrated all-optical control of the conductance in this type of device. [21,28] The mechanism involved can be regarded as an extension of the existing models, that is, light stimuli at different wavelengths can induce the trapping/detrapping of the electrons or an increase/reduction in the number of trapping centers.…”

Electrodeposition of GeSbTe-Based Resistive Switching Memory in Crossbar Arrays

“…This resistive switching phenomenon is most likely associated with the repeated formation and rupture of local conductive filaments (CFs), although interfacial-/bulk-based switching has been also reported . Resistive switching has been observed in a wide range of materials, such as binary metal oxides, − perovskites, − 2D materials, ,− organics, − and organic–inorganic composite materials. ,,− …”

Impedance Spectroscopy of Hierarchical Porous Nanomaterials Based on por-Si, por-Si Incorporated by Ni and Metal Oxides for Gas Sensors

“…The observed effects can be explained by the formation of a percolation merged cluster under conditions slightly exceeding the percolation threshold. The technical devices implemented at the percolation threshold are certainly of great interest [48][49][50][51]. In such structures, when interacting with oxygen, the percolation cluster breaks off.…”