Anodic Oxidation of Ultra-Thin Ti Layers on ITO Substrates and their Application in Organic Electronic Memory Elements

In this work, controlled anodic oxidation is reported for ultra-thin (3 nm thick) titanium layers on indium tin oxide (ITO) coated glass substrates. A physical explanation is also provided for the origin of the delamination process of the Ti during the anodic oxidation. The properties of the fabricated layers are studied using electrochemical impedance spectroscopy (EIS) and X-ray Photoelectron Spectroscopy (XPS). In addition, one intriguing application is demonstrated for the anodized layers: their use as an interfacial barrier in organic diodes. Diodes containing an electrochemically fabricated TiO2 barrier layer exhibit clear room temperature negative differential resistance (NDR) and a peak-to-valley current ratio (PVCR) of 3.6. The reference diodes without the TiO2 layer show normal diode characteristics with no observable NDR. The NDR diodes have potential applications as memory elements for large-area electronics.