Low-voltage organic transistors with titanium oxide/polystyrene bilayer dielectrics

Abstract

Pentacene-based low-voltage organic transistors were realized with titanium oxide/polystyrene (TiO2/PS) bilayer dielectrics. Significantly, the TiO2 bottom layer was fabricated by a layer-by-layer deposition procedure and had an ultrathin thickness (<5 nm). The nonpolar PS top layer not only shields out the high polarity TiO2 layer, but also reduces the roughness of the dielectric, which results in low gate leakage of dielectric and the more ordered growth of pentacene film. This organic transistor with a TiO2/PS bilayer dielectric was found to exhibit high performance with a low operating voltage (≤3 V), and a high on/off ratio (>107).