Control of the nano electrostatic phenomena at a pentacene/metal interface for improvement of the organic FET devices

Abstract The effect of the UV/ozone treatment of substrate on transistor properties of the bottom contact pentacene FET is discussed in the context of the carrier accumulation around the source-drain electrode. Significant change of the threshold voltage, i.e., the decrease of the V th , by a UV/ozone treatment of the substrate was observed, and can be reasonably assigned to accumulated charges around source-drain electrode. In addition, to investigate the channel formation process on this FET, capacitance–voltage ( C – V ) characteristics were measured, and significant difference between UV/ozone-treated and untreated FET was observed. Only a small change of a capacitance was observed for untreated sample with applied voltage, whereas drastic increase of the capacitance was observed for UV/ozone-treated FET. The capacitance increase corresponds to the accumulation of carriers at the interfacial region of pentacene, and this behavior was in good agreement with the result of the FET measurement. Finally, these C – V characteristics were successfully reproduced by Maxwell–Wagner model.

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