Instability for organic field effect transistors caused by dipole on insulator surface

The influence of the dipole of an insulator surface on temporal changes in the source-drain current was investigated by using organic field-effect transistors with a surface-modified SiO₂ insulator. The source-drain current decreased drastically with respect to time when the dipoles of the insulator surface displaced slightly. In order to obtain highly stable organic transistors, it is thus necessary to remove the mobile dipoles from the insulator surface.