Preparation And Characteirzation Of OFET

Compared with the traditional transistor, Organic Field-effect Transistors (OFET) havethe advantage of low-costing and flexible, they own wide range of potential applications onthe flexible display of large area and transducer and other fields. The efficient path to reducecosts of OFET is development all-solution process, including organic semiconductor filmsand dielectric films. there are PI、PVP、PVA、PMMA and others in the aspect of polymerdielectric materials, and PVP has higher dielectric constant, so we can fabricate it to biggergate capacitance per unit area and lower the working voltage. But when we got PVP dielectricfilms under30nm by solution process, it had large leakage current density, so it is the keywork to research process of low-leakage current and thickness for all-solution process ofOFET. There are many paths to fabricate low-leakage current PVP films, including addingdifferent crosslinking agent, changing their quality percentages, fabricating complex filmslike PVP/PMMA and adding modification layer, but there are no articles of the improvementof the process in spinning or annealing. In a different way, this paper’s emphasis isimprovement of the process in order to fabricate ultrathin and low-leakage current PVP films.The main contents include:(1) The influence of solvent-vapor-assisted spinning to PVP films. In order to achieveultrathin films, we compounded PGMEA、PVP and PMF to crosslinked PVP precursorsolution. We controlled the solution’s spinning around the vapor of organic solvent. It wasfound that we could achieve10nm-thickness PVP dielectric films with2wt%qualitypercentage crosslinked PVP precursor solution by anhydrous ethanol vapor and thecapacitance per unit reached to442nF/cm2(dielectric constant was measured of5.0).(2) The influence of solvent-vapor-assisted annealing to PVP films. It was found that thePVP films’ surface topography had changed after solvent-vapor-assisted spinning. We wish toget ultrathin PVP films and their surface topography is lower. We took process of assistedannealing before vacuum annealing, and controlled this process under the airtight condition.By the anisole-vapor-assisted annealing, films’ average surface roughness were decreasedfrom0.36nm to0.21nm, and the trap density in films were decreased by26%analyzed bySCLC.