Solution-Processed TiO2-Based Schottky Diodes with a Large Barrier Height

Thin-film Schottky diodes are one of the key elements in large-area flexible electronics. In such devices, a highly uniform semiconductor film is vital for the device performance. Here we propose a novel solution-based anodization method to form a conformal oxide semiconductor layer for Schottky diodes. The thickness of the anodized TiO2 layer varied from 12 to 22.5 nm. The optimized Pt/TiO2/Ti Schottky diode demonstrated a large barrier height of 1.19 eV, an on/off ratio as high as 3.5 x 106 at ± 2 V, and an ideality factor of 1.5. The average breakdown electric field was 5.5 MV/cm, which is higher than typical values of conventional solution processed TiO2. The diode with a 15-nm-thick TiO2 layer also showed good rectification properties up to 0.7 MHz.