Function of interfacial dipole monolayer in organic field effect transistors

The effect of interfacial dipole monolayer on carrier injection property of pentacene OFET was studied to understand the origin of contact resistance, which was evaluated from a modified transmission line model. The results showed the contact resistance of pentacene OFET with the dipole monolayer is much higher. This large discrepancy was found due to a small potential drop difference at the interface generated by the dipole monolayer. In addition, the strong local electric field confirmed the reason for the large negative threshold voltage shift. These studies show the importance of local electric field at pentacene-SiO₂ interface generated by the dipole monolayer.