Facile passivation of solution-processed InZnO thin-film transistors by octadecylphosphonic acid self-assembled monolayers at room temperature

A simple passivation method is developed to overcome the water susceptibility of solution-processed InZnO thin-film transistors (TFTs) by utilizing octadecylphosphonic acid (ODPA) self-assembled monolayers (SAMs). The unpassivated InZnO TFTs exhibit large hysteresis in their electrical characteristics due to the adsorbed water at the semiconductor surface. Formation of a SAM of ODPA on the top of InZnO removes water molecules weakly absorbed at the back channel and prevents water diffusion from the surroundings. Therefore, the passivated devices exhibit significantly reduced hysteretic characteristics.