The electrical properties of triisopropylsilyl (TIPS) pentacene organic thin-film transistors (OTFTs) such
as field-effect mobility, on/off ratio, threshold voltage and subthreshold slope were markedly improved by
employing suspended source/drain (SSD) electrode structure. The SSD structure was fabricated by using
Cr/Au double layer where Cr was used as a sacrificial layer. Using the SSD structure, the field-effect mobility
in the linear region increases from 0.007 cm2/Vs to 0.29 cm2/Vs, on/off ratio from 104 to 107, threshold
voltage decreases from +9 V to -3 V and subthreshold slope decreases from 4.5 V/decade to 0.6 V/decade.
We investigated the electrical stability of polythiophene-based organic thin film transistors (OTFTs). The electrical properties of a thin film transistor such as field effect mobility, threshold voltage and on/off current changed vastly when exposed to air. In order to analyze the stability of the transistor, electrical properties were first measured in vacuum for several hours, then air or oxygen gas was introduced and the changes in the electrical properties were observed. Device showed a decrease in field effect mobility from 10-3 cm2/V•s to 10-5 cm2/V•s after exposure to air and the on/off ratio was also changed from 103 to 101.