Polymer/AlO[sub x] Bilayer Dielectrics for Low-Voltage Organic Thin-Film Transistors

We report on the low-voltage-driven organic thin-film transistors (OTFTs) with various organic films [pentacene, tetracene, and copper-phthalocyanine ] for the semiconductor channel on a thin poly-4-vinylphenol (PVP)/aluminum oxide bilayer gate dielectric. Quite a large capacitance of and a high dielectric strength of were achieved from the bilayer dielectric. All the organic channel layers deposited on the bilayer exhibited good crystalline quality as characterized by both X-ray diffraction (XRD) and atomic force microscopy (AFM) surface imaging because the bilayer had a smoothened and hydrophobic PVP surface on top. Our OTFTs with the bilayer dielectric exhibited good field-effect mobilities of 0.55, 0.07, and for pentacene, tetracene, and channels, respectively, at a low operating voltage of less than .