Influence of Pentacene Film Thickness on Environmental Stability of Pentacene Thin-Film Transistors

We investigated the influence of pentacene film thickness on the environmental stability of thin-film transistors (TFTs). In order to evaluate the environmental stability, the transfer and output characteristics in pentacene TFTs were measured in air and vacuum environments. The pentacene-thickness-dependent variation of transfer characteristics was shown to originate from the fixed charge at the pentacene/polymeric insulator interface induced by air molecules. In addition, an analysis of parasitic resistance suggests that air molecules degraded the contact property and increased channel conductivity. Particularly, a thick pentacene film was found to passivate the TFT channel region interrupting the penetration of air molecules.