Organic Transistors that Use Source/Drain Electrodes Supported by High Resolution Rubber Stamps

Soft contact lamination and metal-coated elastomeric stamps provide the basis for a convenient and non-invasive approach to establishing high resolution electrical contacts to electroactive organic materials. The features of relief on the stamp define, with nanometer resolution, the geometry and separation of electrically independent electrodes that are formed by uniform, blanket evaporation of a thin metal film onto the stamp. Placing this coated stamp on a flat substrate leads to 'wetting' and atomic scale contact that establishes efficient electrical connections. When the substrate supports an organic semiconductor, a gate dielectric and a gate, this soft lamination process yields high performance top contact transistors with source/drain electrodes on the stamp. We use this approach to investigate charge transport through pentacene in transistor structures with channel lengths that span more than 3 decades: from 250 mum to ~150 mum.