Role of Ti interfacial layer in the stability of TiO2 based transparent synaptic device

Abstract

Interface engineering plays a pivotal role in manipulating the electrical transport and conduction mechanism of a synaptic device. In this work, the impact of Ti as an interfacial layer is systematically investigated by inserting ∼5 nm thin film at both interfaces of a functional layer (TiO₂). Interestingly, it was observed that Ti layers significantly regulate the migration of oxygen ions/vacancies at the interfaces yielding an improved stability from 10 to 200 cycles, sustained over a longer period ∼8 × 10³ s. Forming free and gradual transition in conductance on positive bias region under a controlled compliance current ∼0.3–17 mA demonstrates the multilevel switching highlighting the typical synaptic behavior of memristor. The ohmic conduction and space charge-limited current mechanism was found across the various resistive states signifies the trapping/de-trapping. Besides, other key parameters of synaptic device such as paired pulse facilitation, depression, and short-term memory together with the excellent transmittance in the visible spectral range makes our device adequate for innovative transparent neuromorphic applications.