Organic Permeable Base Transistors for Flexible Electronic Circuits

Organic Permeable Base Transistors (OPBT) with C60 as a small-molecule semiconductor show impressive characteristics due to their short vertical channel in the range of 100 nm. Current densities exceeding 10 A/cm² and large on/off ratios have recently been published for samples processed on glass. [1] The outstanding frequency behavior that allows for operation in the MHz-regime at a low operation voltage makes OPBTs attractive for applications in wireless communication while allowing simple processing in a single vacuum evaporation tool without the need for expensive structuring like µm range lithography. Our current work aims at processing these devices on flexible plastic substrates. Transistor and circuit operation in real application scenarios require air-stability, which necessitates encapsulation. We employ AlOx thin-films from Atomic Layer Deposition (ALD) to protect OPBTs from external degradation to facilitate long-term stable, flexible, organic electronics. The easy structuring and the high-current capability of our transistors will enable versatile applications like for instance wireless communication, flexible displays or sensor applications with a technology that allows for low cost production. [1] Klinger, M. P.; Fischer, A.; Kaschura, F.; Scholz, R.; Lüssem, B.; Kheradmand-Boroujeni, B.; Ellinger, F.; Kasemann, D. & Leo, K. Advanced Materials, 2015, 27, 7734–7739