Modulation in optical second harmonic generation signal from channel of pentacene field effect transistors during device operation

Abstract

The channel formation process of the pentacene field effect transistor (FET) was shown by the optical second harmonic generation (SHG) ascribed to the electric field induced SHG. The SHG signal probed successfully and nondestructively the off and on states. The enhancement of the SHG signal at the off state was observed with applying the source-drain voltage in the absence of the gate voltage, whereas it remarkably decayed with applying the gate voltage, indicating the channel formation. At the channel formation, holes injected from the source electrode changed the potential profile in pentacene film at the off state and the SHG signal was suppressed.