Analyzing the influence of negative gate bias stress on the transconductance of solution-processed, organic thin-film transistors

作者：Sprogies J; Scheinert S^*; Hoerselmann I

来源：Journal of Applied Physics, 2014, 116(7): 074507.

DOI：10.1063/1.4893317

We have investigated the bias stress stability of poly(3-hexylthiophene) (P3HT)-based organic field-effect transistors (OFETs), prepared from chloroform or trichlorobenzene solutions on a thin SiO2 dielectric (bottom gate) with an additional self-assembled monolayer. Three different processes of gate oxide treatment were compared with regard to their reaction to prolonged constant gate bias. Furthermore, we analyzed the transconductance g(m) during gate bias stress, as well as the contact resistance R-c using the transmission line method and found that the bias stress has no influence on the contact resistance of P3HT-based OFETs, but with the addition that R-c strongly affects g(m). The most stable characteristics were achieved for transistors with a dielectric coated with hexamethyldisilazane over 22 h, which exhibited a pronounced reduction of the threshold voltage shift and contact resistance in comparison with the other variants of gate dielectric treatment. Based on two-dimensional simulations, we demonstrate that an increased R-c in combination with a carrier concentration dependent, high mobility leads to a maximum in the transconductance curve, which can be prevented by optimizing the contact between source/drain and the channel region.

• 出版日期2014-8-21