High-Performance Organic Field-Effect Transistors Fabricated with High-k Composite Polymer Gel Dielectrics

Abstract

This study presents a composite gel-like dielectric material for organic field-effect transistors (OFET) applications. Poly(methyl methacrylate) (PMMA) gelled with propylene carbonate was used as gel dielectric material. Copper phthalocyanine was used as active layer in the OFET structures. In order to enhance the performance of the PMMA-gel dielectric material, silicium dioxide (SiO2) was used as an additive material. Various ratios of SiO2 were added to the gel dielectric and the effect of SiO2 on the OFET performance was investigated. It was clearly observed that SiO2 enhanced the performance and source-drain current of the fabricated OFETs. SiO2 was added to the PMMA-gel with different doping ratios of 0%, 10%, 30%, 50% and 100% by using a solution-processing method. The dielectric properties of the PMMA-gel:SiO2 composite materials were analyzed with impedance spectroscopy in terms of their effective capacitance ©I), tangent factor (tan(δ)), phase angle and complex dielectric constant (e′ and e″). The hole mobility of the OFETs was enhanced by 50% SiO2 nanoparticles in PMMA-gel dielectric materials from 6.83 × 10−1 cm2 V−1 s−1 to 4.66 × 100 cm2 V−1 s−1 (at VDS = − 0.5 V). The time-dependent IDS curves were analyzed for OFETs fabricated with PMMA-gel:SiO2 composite dielectric layers. It was found that all the devices worked stably under bias stress and gave fast responses for all gate voltages.