Effect of Head Groups in Self-Assembled Monolayer Passivation on Properties of InSnZnO Thin-Film Transistors

Self-assembled monolayers (SAMs) with three different head functional groups are prepared as passivation layers (PVLs) for amorphous InSnZnO (ITZO) thin-film transistors (TFTs). Head groups exhibit considerable modulation of surface topography and surface energy, leading to a difference in the passivation effect. This variation is attributed to the discrepancy of the binding methods determined by the head groups. Additionally, the head groups also modulate the relative direction and strength properties of dipoles at ITZO surface, which affects the surface potential and carrier density in ITZO films. As a consequence, the electric performance and stability of devices can be modulated by head groups in SAMs. These results provide a likely and low-cost method to ameliorate the capability of TFTs.