Embodiments herein describe techniques for a thin-film transistor (TFT) above a substrate. The transistor includes a gate electrode above the substrate, and a channel layer above the substrate, separated from the gate electrode by a gate dielectric layer. The transistor further includes a contact electrode above the channel layer and in contact with a contact area of the channel layer. The contact area has a thickness determined based on a Schottky barrier height of a Schottky barrier formed at an interface between the contact electrode and the contact area, a doping concentration of the contact area, and a contact resistance at the interface between the contact electrode and the contact area. Other embodiments may be described and/or claimed.