화학공학소재연구정보센터
Applied Surface Science, Vol.336, 11-15, 2015
Laser-induced forward transfer of multi-layered structures for OTFT applications
We report on the one-step laser printing of multi-layered organic-based field effect transistors, using thin films of bis(2-phenylethynyl) end-substituted terthiophene (diPhAc-3T) as semiconductor, parylene-C(Py-C) as dielectric and silver (Ag) as gate electrode, respectively. The laser-induced forward transfer(LIFT) process was used to transfer pixels from donor to receiver substrates. The latter included pre-designed source and drain gold electrodes to form complete organic thin films transistors (OTFTs). Such laser-induced forward transfer used a single 50 ps duration pulse delivered by a Nd: YAG laser operatingat 355 nm to print transistor pixel arrays under ambient temperature. The pixels (350 mu m sized-squares, and 700 + 40 nm in thickness), fabricated in the top gate configuration, were investigated for their current-voltage characteristics immediately after printing. Electrical characterization demonstrated that the laser printed transistor is fully functional with hole mobilities of 4 x 10(-4) cm(2)/V s, a threshold voltage V-t near -10 V, I-on/I-off ratio near to 10(4)-10(5) and the sub-threshold slope (S) of 14-18 V/decade. The efficient cohesion between the three different layers composing the pixels offers an exceptionally high strength to laser printing, while maintaining the electrical properties. (C) 2014 Elsevier B.V. All rights reserved.