December 1-6, 2013 | Boston
Meeting Chairs: Charles Black, Elisabetta Comini, Gitti Frey, Kristi Kiick, Loucas Tsakalakos
The high operative voltages and the low mobility of semiconductors are probably the most relevant problems that have affected so far organic electronics devices and have significantly limited their employment in practical applications.Many attempts of solving these problems have been done, aiming at a better performance of organic semiconductors. We believe that an as important route for achieving the final goal consists in improving the device architecture, aiming, at the same time, at a fabrication procedure able to be easily scaled up for industrial production.By combining an ultra-thin dielectric layer with a self-aligned architecture, Organic Thin-Film Transistors (OTFTs) with ultra-low operational voltages (<2 V) and a very high (100 kHz) cut frequency have been obtained, with a traditional, low mobility organic semiconductor as Pentacene. The devices are fabricated using a one-mask, photolithographic self-alignment technique that can be realized with standard photoresists and without further chemical treatments. This technique allows a dramatic reduction of the parasitic capacitances thus leading to a remarkable increase of the cut-off frequency, even with organic semiconductors with a relatively low mobility. In this contribution, the main electrical parameters of ultra-low voltage, self-aligned devices are reported, and a complete frequency characterization of the devices is given. These characteristics make the reported approach suitable for the development of basic circuitries for high frequency applications. In addition, optimized structures may be successfully employed for the realization of OTFT-based sensor devices, that also greatly benefit of the reduction of operating voltages and optimization of the frequency performances.
Getting away from oxide dielectrics in organic field-effect transistors (OFETs) is not only cost-effective but has tremendous advantages for improving carrier mobility and sta