Solution Processed Organic and Inorganic Transistors – Application in Inverter Circuits

In the fabrication of organic field-effect transistors (FETs), the usage of high κ dielectrics lowers the operating voltage and enhances device performance. Polymer ferroelectrics open the path not just for high κ values but allow processing of the films via electrical poling. Poled ferroelectric dielectrics in p-type organic FETs is seen to improve carrier mobility and reduce parasitic current when compared to unpoled devices using the same dielectric. Furthermore, n-type inorganic FETs using solution processed ZnO have shown improved performance when the semiconductor layer is subjected to a UV-ozone treatment. FETs were fabricated using the ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) as the dielectric insulator and the electron donor-acceptor polymer diketopyrrolopyrrole-dithienylthieno[3,2-b]thiophene (DPP-DTT) for the semiconductor layer, with devices showing mobilities as high as 0.4 cm²/Vs when electrical poling was utilized. ZnO thin film FETs were fabricated with SiO₂ as the dielectric layer, yielding carrier mobilities on the order of 10^-2 cm²/Vs. Both p- and n-type FETs were used in a voltage inverter circuit, showing promising characteristic gain.