High-performance pentacene-based thin-film transistors and inverters with solution-processed barium titanate insulators

High-performance pentacene-based thin-film transistors and inverters with solution-processed barium titanate (BTO) insulators are demonstrated. The current-voltage characteristics of the transistors show high mobility of 9.53 cm^{2}\hbox{V}^{-1}\hbox{s} ^-1 at smaller V-{G} = -\hbox{3.5}\ \hbox{V} and V-{D} = -\hbox{5}\ \hbox{V}, a low threshold voltage of -1.5 V, and a subthreshold slope of 599 mV/dec. Large grain and small crystalline sizes are observed from atomic force microscopy images and X-ray diffraction analysis of pentacene films. The results are verified through Raman spectroscopy and a theoretical Marcus-Hush equation to understand the higher intermolecular coupling, resulting in easier carrier transports in pentacene molecules. In order to investigate the behavior of high-permittivity materials of BTO insulators in a logic circuit, simple and low-operating-voltage inverters are fabricated, and the gain is approximately 8.76 under a small operating voltage range from 0 to -5 V.