Towards low voltage resistive switch in sol-gel derived TiO₂/Ta₂O₅ stack thin films

Highlights: • Pt/TiO₂/Ta₂O₅ stacks as memristive building blocks were fabricated by the sol-gel method for the first time. • The developed sol-gel route towards Ta₂O₅ film fabrication relies on relatively inexpensive TaCl₅ precursor. • The fabricated defect-free Pt/TiO₂/Ta₂O₅ stacks represent suitable building blocks for memristor cell fabrication. • The memristive cells, Pt/TiO₂/Ta₂O₅/Pt (tip), displayed a narrow switching voltage window and a high resistance ratio (10³). • The narrow window of the switching voltage in memristor opens a possibility of coupling it to neuron. Herein, we report a memristive response from Pt/TiO₂/Ta₂O₅/Pt stack thin films with low SET and RESET voltages, and resistance ratio of 10³. For the first time, Pt/TiO₂/Ta₂O₅ stack thin films were produced by sol-gel procedure. The morphology and elemental composition of Pt/TiO₂/Ta₂O₅ stacks were studied by a set of complementary techniques, including scanning electron microscopy (SEM), field-emission electron microscopy (FE-SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The thickness of the material was estimated from the transmittance spectrum by Pointwise Unconstrained Optimization Approach (PUMA).