Combinatorial screening of anodic memristors based on Ti-W system for unipolar analog resistive switching applications

Abstract Anodically formed Ti-W oxides are investigated as memristive materials, using a thin-film combinatorial library with W contents ranging from 3 to 20 at%. Across the entire parent metal library, the anodic memristors exhibit forming-free and volatile behavior. All devices display unipolar resistive switching with a gradual, analog conductance regulation. Differences in state and cycling stability are observed with respect to the W content. The low resistance state remains essentially unaffected by composition, while the high resistance state and consequently, the resistance ratios are influenced by the increase in W content. Devices with 3–12 at% W exhibit higher resistance ratios of 10⁷ coupled with steady state stability measurements, but have comparatively lower endurance capabilities (10 4 cycles). In contrast, devices with W contents of 13–20 at% show slightly reduced resistance ratios of 10 6 , but sustain longer cycling lifetimes (10 5 cycles). The best-performing device, identified as Ti-5 at% W, was selected for transmission electron microscopy, which revealed an amorphous oxide layer with distinct crystalline regions. This configuration is believed to be responsible for the an interfacial mechanism observed. Subsequent current conduction analysis confirms Schottky emission as the dominant mechanism based on barrier modulation. Altogether, the results demonstrate anodic Ti-W oxides for tunable, interface-controlled devices suitable for neuromorphic applications.