Flexible Memristors Fabricated through Sol-Gel Hydrolysis

Flexible memristors consisting of an oxide film generated through hydrolysis of a spun-on sol-gel were fabricated on polyethylene terephthalate substrates. X-ray photoelectron spectroscopy, spectroscopic ellipsometry, transmission electron microscopy, and electron energy loss spectroscopy measurements indicated that the oxide films contained amorphous TiO2 as well as a significant fraction of organic material. This characterization indicated that the oxide film has a different structure and morphology than sputter-deposited TiO2 memristors ("traditional memristors"). Despite the structural differences between sol-gel and traditional memristors, these flexible memristors exhibit switching behavior that is similar to sputter-deposited devices. Current-voltage (I-V) measurements suggest that this switching is not directly due to the electric field in the memristors. Additionally, thermal imaging measurements and I-V measurements performed after sectioning the memristors suggest that conduction occurred via localized conduction pathways. Capacitance-frequency and conductance-frequency measurements were also performed to further investigate conduction and loss mechanisms in these memristors.