High-k and low-k nanocomposite gate dielectrics for low voltage organic thin film transistors

CeO2-SiO2 nanocomposite films were used as the gate dielectrics in organic thin film transistors (OTFTs) with pentacene active semiconductor. CeO2-SiO2 composite films exhibited a high dielectric capacitance of 57 nF/cm(2) with exceptionally low leakage current. Good device characteristics were obtained with saturation at low operating voltages (similar to 2 V) and with a field effect mobility of 0.84 cm(2) V-1 s(-1), a threshold voltage of similar to 0.25 V, an on/off current ratio of 10(3), and a subthreshold slope of 0.3 V/decade, whereas the gate leakage current density is considerably lowered. These results should therefore increase the prospects of using OTFTs in low power applications such as portable devices.