Bulk mixed ion electron conduction in amorphous gallium oxide causes memristive behaviour

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Memristive devices offer promising non-volatile memory and neuromorphic computing applications.
• Understanding the switching mechanisms in resistive switching materials is crucial for device optimization.

Purpose of the Study:

• To investigate non-filamentary memristive switching in amorphous gallium oxide (GaOx) thin films.
• To elucidate the role of oxygen ion conductivity in enabling resistive switching behavior.

Main Methods:

• Fabrication of amorphous GaOx thin films sandwiched between ion-blocking electrodes.
• Utilizing photoemission and transmission electron microscopy to observe ion migration.
• Characterizing the electrical transport properties and I-V hysteresis loops.

Main Results:

• Direct observation of reversible oxygen ion enrichment and depletion at electrodes.
• Demonstration of room-temperature memristive switching driven by oxygen ion mobility.
• Tunable hysteresis loop shapes (figure-eight to triangle) influenced by bias history.

Conclusions:

• Oxygen ion conductivity in amorphous GaOx is the primary mechanism for non-filamentary resistive switching.
• The observed memristive behavior is governed by coupled ion drift-diffusion dynamics.
• The oxygen concentration profile acts as a state function, enabling tunable device characteristics.