Investigation of a memory effect in a Au/(Ti-Cu)Ox-gradient thin film/TiAlV structure.

This paper presents the results of the analysis of resistive switching properties observed in a Au/(Ti-Cu)Ox/TiAlV structure with a gradient distribution of Cu and Ti along the (Ti-Cu)Ox thin film thickness. Thin films were prepared via multisource reactive magnetron co-sputtering. The programmed profile of the pulse width modulation coefficient during sputtering of the Cu target allowed us to obtain the designed gradient U-shape profile of the Cu concentration in the deposited thin film. Electrical measurements of the Au/(Ti-Cu)Ox/TiAlV structure showed the presence of nonpinched hysteresis loops in the voltage-current plane testifying a resistive switching behavior. Results of optical, X-ray, and ultraviolet photoelectron spectroscopy measurements allowed us to elaborate the scheme of the bandgap alignment of the prepared thin films with respect to the Au and TiAlV electrical contacts. Detailed structure and elemental profile investigations allowed us to conclude about the possible mechanism for the observed resistive switching mechanism.