Photolithographic source/drain contacts for organic thin film transistors

Organic thin film transistors (OTFT) have great potential in electronic applications. For example, they find use in sensors and a variety of simple and cheap circuits. Organic electronics focuses on implementation fields, where low costs, large area production and the use of flexible and even biological substrates are essential. Pentacene, an organic molecule consisting of five fused aromatic rings, has proven to be of great interest in TFTs. Though early attempts to employ organic active layers produced organic semiconductors with field-effect mobilities six orders of magnitude smaller than silica, pentacene TFTs with SiO2 as gate-dielectric have recently been shown to have mobilities larger than 1 cm2/Vs, rivalling those of amorphous silicon TFTs. Organic dielectrics enable the use of simple processing techniques, such as spin- or dipcoating by being available in liquid or soluble form. In this work we present organic TFTs with Pentacene as an active layer, organic and inorganic dielectric materials and a comparison of organic and inorganic source/drain contact materials. All electrodes (source, drain and gate) of the full-organic transistors were structured by photolithography.