A method is provided for preparing an interface surface for the deposition of an organic semiconductor material, in the fabrication of an organic thin film transistor (OTFT). A substrate is provided and a gate electrode is formed overlying the substrate. A gate dielectric is formed overlying the gate electrode. Then, source (S) and drain (D) electrodes are formed overlying the gate dielectric, exposing a gate dielectric channel interface region between the S/D electrodes. Subsequent to exposing the OTFT to a H2 or N2 plasma, a self-assembled organic monolayer is formed overlying the S/D electrodes. Finally, an active organic semiconductor layer is formed over the S/D electrodes and gate dielectric channel interface. The OTFT may be exposed to plasma either before or after the formation of the S/D electrodes.