Electret-Based Organic Synaptic Transistor for Neuromorphic Computing

Abstract

Neuromorphic computing inspired by the neural systems in human brain will overcome the issue of independent information processing and storage. An artificial synaptic device as a basic unit of a neuromorphic computing system can perform signal processing with low power consumption, and exploring different types of synaptic transistors is essential to provide suitable artificial synaptic devices for artificial intelligence. Hence, for the first time, an electret-based synaptic transistor (EST) is presented, which successfully shows synaptic behaviors including excitatory/inhibitory postsynaptic current, paired-pulse facilitation/depression, long-term memory, and high-pass filtering. Moreover, a neuromorphic computing simulation based on our EST is performed using the handwritten artificial neural network, which exhibits an excellent recognition accuracy (85.88%) after 120 learning epochs, higher than most reported organic synaptic transistors and close to the ideal accuracy (92.11%). Such a novel synaptic device enriches the diversity of synaptic transistors, laying the foundation for the diversified development of the next generation of neuromorphic computing systems.

Reconfigurable Multifunctional Ambipolar Polymer Transistors with Improved Switching-off Capability Upon Non-Uniformly Distributed Compensation Potential

“…6, introducing uniformly trapped charges only shifted the transfer curves to positive or negative voltages, and the current on/off ratios were almost unchanged. The transfer curve shifts were originated from the trapped charges in the insulatormatrix, which modulated the accumulation and depletion of mobile charges by the electrostatic interaction 14,55 . Stressing the transistor with positive gate voltages could inject electrons into the insulator-matrix and the trapped electrons will enhance the accumulation of holes while suppress the accumulation of electrons, which shifted the transfer curves to positive voltages.…”

“…When the nerve impulses are transmitted to the synaptosomes through the axon, the presynaptic membrane releases neurotransmitters to the synaptic cleft, and the neurotransmitters diffuse to the post-synaptic membrane and bind to protein receptors, causing excitatory or inhibitory changes in the post-synaptic membrane (Fig. 4d) 14,40,68 . The function of synapse could be emulated in ambipolar transistor with electret, where holes or electrons serving as the transmitters could be trapped in the electret under the gate pulse to convert the gate pulse carried signals into the change of drain current (Fig.…”

“…Reconfigurable devices with modifiable operating states or multiple functions are quite meaningful for the miniaturization of circuits, by reducing the number of devices, promoting the integration of circuits, and endowing the circuits with versatility 2, [8][9][10] . In addition, neural-like electronic devices and neuromorphic computing that mimics the human brain provide an efficient information processing method [4][5][6][11][12][13][14][15][16] . Nevertheless, this also places higher demands on the functions of devices and circuits 8,17 .…”

“…Nevertheless, this also places higher demands on the functions of devices and circuits 8,17 . A single device which can emulate the synapses with the functions of both signal transmission and non-volatile memory is indispensable for neuromorphic electronics 5,14,18 .…”

“…Three states for both p-type and n-type operation with current ratios of 10 2 , 10 3 and 10 5 to each other are obtained with the retention time exceeding 10 4 s. Furthermore, the non-uniform charge trapping in these reconfigurable ambipolar transistors is applicable for emulating the biological synapses. Both holes and electrons could serve as neurotransmitters to be reversibly injected and trapped in the electret to modulate the drain current representing the variation of post-synaptic signals 5,14,40 .…”