Solution-processed, flexible, and highly transparent ZrO2:PVP hybrid dielectric layer

Organic-inorganic hybrid dielectric layers have attracted extensive attention due to their ability to simulta-neously improve the relative dielectric constant (k) and mechanical properties of gate dielectric layers, and have great potential in flexible and wearable displays. This paper reports a low-temperature deposition method of high-quality Zirconium (IV) dioxide (ZrO2) and Polyvinylpyrrolidone (PVP) hybrid gate dielectric layers by sol -gel method. The hybrid films have a smooth morphology, low roughness, high transmittance of 95% in the wavelength range higher than 320 nm, and an optical bandgap of up to 5.63 eV. The leakage current density (J) of the hybrid film is as low as 6.85 x 10-6 A/cm2 at 1 MV/cm, and no breakdown phenomenon was observed when electric fields up to 2 MV/cm were applied. In addition, enhanced interface polarization occurred between PVP and ZrO2, thereby increasing the hybrid film's k, resulting in a high-k (32.3 at 1 kHz). The fabricated films also exhibited good flexibility and maintain excellent insulation after 200 times of bending with a radius of 10 mm. Finally, low operating voltage thin film transistors (TFTs) using these high k ZrO2:PVP dielectrics were obtained and a threshold voltage of 0.05 V and on/off current ratio of 1.24 x 105 were measured. The results demonstrate that the fabricated hybrid films are ideal gate dielectric materials for flexible wearable and low power consumption devices.