Field Driven Solid-State Defect Control of Bilayer Switching Devices: Ionic Transport Kinetics within Layers and...

Area of Science:

• Materials Science
• Nanotechnology
• Solid-State Ionics

Background:

• Nanoionic devices are vital for neuromorphic computing and actuators but are often limited by ion transport kinetics.
• Distinguishing ion transport within layers from interfacial transfer in bilayer systems is experimentally challenging.
• This difficulty hinders the rational optimization of device performance.

Purpose of the Study:

• To develop and apply a novel dynamic current-voltage (I-V) technique for deconvoluting ion transport in bilayer nanoionic systems.
• To isolate and quantify intralayer ion transport kinetics and interlayer ion transfer kinetics.
• To identify and characterize interfacial energy barriers affecting ion mobility.

Main Methods:

• Extension of the dynamic current-voltage (I-V) technique to a PrₓCe₁₋ₓO₂/La₂₋ₓCeₓCuO₄ (PCO/LCCO) bilayer system.
• Utilizing varying sweep rates to differentiate between intralayer and interlayer ion transport.
• Applying Arrhenius analysis to determine activation energies for different transport processes.

Main Results:

• Quantified intralayer oxygen vacancy mobility in the PCO layer, showing strong dependence on defect concentration (2.06–7.31 × 10⁻¹² cm² V⁻¹ s⁻¹ at 50 °C).
• Determined activation energies for intralayer transport (0.69–0.86 eV).
• Identified a distinct kinetic signature for interlayer ion exchange at lower sweep rates, with a higher activation energy (1.03 ± 0.1 eV), indicative of an interfacial energy barrier.

Conclusions:

• The dynamic I-V technique successfully isolates and quantifies distinct ion transport processes in PCO/LCCO bilayers.
• An interfacial energy barrier significantly impacts interlayer ion transfer, rather than bulk diffusion.
• This methodological framework enables optimization of ion transport kinetics for improved nanoionic device speed and performance.