Synaptic Characteristics and Neuromorphic Computing Enabled by Oxygen Vacancy Migration Based on Porous In₂O₃ Electrolyte-Gated Transistors

Abstract

The migration of oxygen vacancies is decisively affecting the modulation of channel conductance. However, for electrolyte-gated transistors (EGTs), the modulation of channel conductance driven by the migration of oxygen vacancies can be easily concealed by the existence of an electrical double layer (EDL). Here, we first observed the modulation of channel conductance caused by the migration of oxygen vacancies, marked by a clockwise transfer hysteresis, by keeping the top gate electrode at a far distance from the source/drain electrodes. The contribution degree of the migration of oxygen vacancies and the EDL on the modulation of channel conductance can be adjusted by changing the distance between the top gate and source/drain electrodes. The results were supported by X-ray photoelectron spectroscopy measurements and first-principles calculations. Due to the migration of oxygen vacancies, the proposed porous In2O3 EGT could emulate biological synaptic functions, such as long-term potentiation/depression, paired-pulse facilitation/depression, image learning, and memorizing. A convolutional neural network based on EGTs is constructed to identify the traffic sign data sets with a recognition accuracy of 91.3%. The porous nature of the developed EGT improved both the long-term memory and the neuromorphic computing properties. From the provided results, a deep understanding of the underlying mechanism of the modulation of channel conductance composed of EGTs is provided. Moreover, our work paves the way for the fabrication of next-generation high-performance artificial synapses.

Investigation on Synaptic Adaptation and Fatigue in ZnO/HfZrO-Based Memristors under Continuous Electrical Pulse Stimulation

“…Instead, a decay in the post-synaptic current is observed during the off period of the pulse, resembling memory loss in biological systems. It is well known that PPF is associated with incomplete compensation of oxygen vacancies [29][30][31]. After the first pulse, oxygen vacancies can be compensated for by oxygen, and if the pulse interval is small enough, the oxygen vacancies will not be fully compensated, thus the conductive channel does not completely disappear, resulting in a higher post-synaptic current after the second pulse [29,32].…”

In2O3/ZnO heterojunction thin film transistor for high recognition accuracy neuromorphic computing and optoelectronic artificial synapses

“…Both films exhibit smooth and crack-free surfaces. The original ZrO x film exhibits a root mean square (RMS) value of 0.6 nm, and Li + doping leads to a moderate increase in RMS value [20]. We analyzed the LiZrO film using x-ray photoelectron spectroscopy (XPS).…”

“…When smaller pulses are used and the external electric field is removed, the mobile ions return to their original positions before the next voltage is applied. This process is known as STP [20]. However, with larger pulses, ions penetrate the channel, causing electrochemical doping [29].…”