Diffusion-Controlled Faradaic Charge Storage in High-Performance Solid Electrolyte-Gated Zinc Oxide Thin-Film...

Area of Science:

• Materials Science
• Neuroscience
• Electrical Engineering

Background:

• Electrochemical devices offer advantages for neuromorphic systems, but supercapacitor-based designs suffer from low memory retention.
• Developing ultralow power neuromorphic systems requires efficient synaptic emulation with long retention times.

Purpose of the Study:

• To demonstrate a solid electrolyte-gated ZnO thin-film device with a battery-controlled charge storage mechanism for synaptic behavior.
• To analyze the device's electrochemical properties and its ability to emulate spike-timing-dependent plasticity (STDP).

Main Methods:

• Fabrication of a solid electrolyte-gated ZnO thin-film device with a tantalum oxide interface.
• Electrochemical analysis using cyclic voltammetry and chronoamperometry.
• Emulation of STDP using multiple in-plane gates.

Main Results:

• The device exhibits battery-controlled charge storage via mobile charges, distinguishing it from supercapacitor-based devices.
• Faradaic-type diffusion-controlled charge storage leads to enhanced channel conductance and a high ON-OFF ratio (10^8-10^9).
• The device successfully emulates STDP at biological synapse timescales due to nonvolatile interface charge storage and slow ion diffusion.

Conclusions:

• The demonstrated ZnO thin-film device offers a promising approach for ultralow power neuromorphic systems.
• The battery-controlled charge storage mechanism provides superior memory retention and synaptic emulation capabilities.
• The use of multiple in-plane gates simplifies STDP emulation, reducing the need for complex waveform-shaping circuits.