Polymer thin-film transistors with chemically modified dielectric interfaces

The characteristics of polymeric thin-film transistors can be controlled by chemically modifying the surface of the gate dielectric prior to the deposition of the organic semiconductor. The chemical treatment consists of derivatizing the silicon oxide surface with organic trichlorosilanes to form self-assembled monolayers (SAMs). The deposition of an octadecyltrichlorosilane SAM leads to a mobility of 0.01-0.02 cm²/V s in a polyfluorene copolymer, a 20-fold improvement over the mobility on bare silicon oxide. The mobility enhancement mechanism is likely to involve molecular interactions between the polymer and the SAM.