Achieving saturation in vertical organic transistors for organic light-emitting diode driving by nanorod channel geometric control

When conventional field-effect transistors with short channel length suffer from non-saturated output characteristics, this work proposed a vertical channel transistor to operate like a solid-state vacuum tube and exhibit good saturated curves. We utilized deep ultra-violet interference lithography to produce ordered grid-like metal to control the potential profile in vertical channel. We compared experimental and simulated characteristics to investigate the keys to achieve saturation. Finally, with an optimized design, a vertical organic transistor is used to drive a solution-processed white-light organic light-emitting diode to perform a luminescence control (0-260 cd/m(2)) with a 3.3-V base potential swing. (C) 2013 AIP Publishing LLC. [10.1063/1.4802999

Deep ultraviolet laser direct write for patterning sol-gel InGaZnO semiconducting micro/nanowires and improving field-effect mobility

Deep-UV (DUV) laser was used to directly write indium-gallium-zinc-oxide (IGZO) precursor solution and form micro and nanoscale patterns. The directional DUV laser beam avoids the substrate heating and suppresses the diffraction effect. A IGZO precursor solution was also developed to fulfill the requirements for direct photopatterning and for achieving semi-conducting properties with thermal annealing at moderate temperature. The DUV-induced crosslinking of the starting material allows direct write of semi-conducting channels in thin-film transistors but also it improves the field-effect mobility and surface roughness. Material analysis has been carried out by XPS, FTIR, spectroscopic ellipsometry and AFM and the effect of DUV on the final material structure is discussed. The DUV irradiation step results in photolysis and a partial condensation of the inorganic network that freezes the sol-gel layer in a homogeneous distribution, lowering possibilities of thermally induced reorganization at the atomic scale. Laser irradiation allows high-resolution photopatterning and high-enough field-effect mobility, which enables the easy fabrication of oxide nanowires for applications in solar cell, display, flexible electronics, and biomedical sensors