Quantitative analysis of the density of trap states at the semiconductor-dielectric interface in organic field-effect transistors

The electrical properties of organic field-effect transistors are governed by the quality of the constituting layers, and the resulting interfaces. We compare the properties of the same organic semiconductor film, 2,8-difluoro-5,11-bis (triethylsilylethynyl) anthradithiophene, with bottom SiO2 dielectric and top Cytop dielectric and find a 10x increase in charge carrier mobility, from 0.17 +/- 0.19 cm(2) V(-1)s(-1) to 1.560.70 cm(2) V(-1)s(-1), when the polymer dielectric is used. This results from a significant reduction of the trap density of states in the semiconductor band-gap, and a decrease in the contact resistance. (C) 2015 AIP Publishing LLC.