A thin film transistor having an improved gate dielectric layer is disclosed. The gate dielectric layer comprises a poly(4-vinylphenol-co-acrylonitrile) based polymer. The resulting gate dielectric layer has a high dielectric constant and can be crosslinked. Higher gate dielectric layer thicknesses can be used to prevent current leakage while still having a large capacitance for low operating voltages. Methods for producing such gate dielectric layers and/or thin film transistors comprising the same are also disclosed.