Organic/inorganic hybrid gate dielectric for high-performance and low-power organic thin-film transistors

High-performance and low-voltage OTFTs have been demonstrated by employing a multilayer dielectric structure where ultrathin PVP (8 nm) is coated on top of high-κ HfLaO (20 nm). The multilayer dielectric exhibited a low leakage current density of 4.6×10^-8 A/cm² at -3 V while maintaining a high capacitance density of 340 nF/cm². The device with the multilayer dielectric showed superior performance as compared to that of the device with single HfLaO (20 nm) dielectric such as a low threshold voltage (V_T) of 0.5 V, a low subthreshold slope (SS) of 0.09 V/decade, a high on-off current ratio (I_on/I_off) of 5×10⁵ and a saturation mobility (μ_SAT) of 0.34 cm²V^-1s^-1 along with a low operating voltage of -2 V. Due to the enhanced μ_SAT with the high gate capacitance of the device with multilayer dielectric, we also achieved a high μ_SATC_ox of 114 nF/Vs, thereby leading to superior drain current drivability.