Embodiments herein describe techniques for a thin-film transistor (TFT), which may include a substrate and a transistor above the substrate. The transistor includes a channel layer above the substrate, a gate dielectric layer adjacent to the channel layer, and a gate electrode separated from the channel layer by the gate dielectric layer. The gate dielectric layer includes a non-linear gate dielectric material. The gate electrode, the channel layer, and the gate dielectric layer form a non-linear capacitor. Other embodiments may be described and/or claimed.