Transfer Printing of Pentacene Thin-Film Transistors onto Flexible Substrates

Transfer printing methods were optimized to fabricate high quality organic thin-film transistors (TFT) on flexible substrates. Flexible TFT devices fabricated from a 50 nm thick pentacene (Pn) semiconductor layer, a 600 nm thick polymer dielectric layer and Au electrodes on a polyethylene terephthalate (PET) substrate constitute a model system. A set of TFT devices with length L = 1 $\mu $m to 45 $\mu $m and width W = 100 $\mu $m were fabricated with both poly(methyl methacrylate) (PMMA) and poly(4-vinylphenol) (PVP) as the dielectric material. Output and transfer IV characteristics of these devices were measured as a function of L. The data sets were analyzed to determine both contact resistance and mobility. The Pn/PMMA/PET device set exhibited a contact resistance of 2 M$\Omega $ and a mobility of 0.237 cm$^{2}$/Vs while the Pn/PVP/PET device set exhibited a contact resistance of 0.5 M$\Omega $ and a mobility of 0.2 cm$^{2}$/Vs. A detailed comparison of these transfer printed device sets will be presented. *Work supported by the Laboratory for Physical Sciences, College Park, MD and ARDA.