Performance Improvement of Organic Thin Film Transistors Based on Gate Insulator Polymethyl-Methacrylate-co-Glyciclyl-Methacrylate

Organic thin transistors (OTFTs) on indium tin oxide glass substrates are prepared with polymethyl-methacrylate-co-glyciclyl-methacrylate (PMMA-GMA) as the gate insulator layer and copper phthalocyanine as the organic semiconductor layer. By controlling the thickness, the average roughness of surface is reduced and the OTFT performance is improved with leak current decreasing to 10^-11A and on/off ratio of 10⁴. Under the condition of drain-source voltage -20V, a threshold voltage of -3.5V is obtained. The experimental results show that PMMA-GMA is a promising insulator material with a dielectric constant in a range of 3.9--5.0.