Enhanced performances of organic thin film transistors by dual interfacial modification of dielectric layer

Abstract

In this paper, we demonstrate an effective method for the performance improvement of organic thin film transistors (OTFTs), in which the SiO2 dielectric layer was dually modified with polystyrene (PS) and hexamethyldisilazane (HMDS) self-assembled monolayer. The relationship between interfacial modification and device performance of OTFTs was systematically investigated. With the dual HMDS/PS modification, the SiO2 dielectric film turns from intrinsically hydrophilic surface to hydrophobic one. Moreover, the dual HMDS/PS modification induces the ordered growth of pentacene layer with large grains up to about 1.5 μm. As a result, the performance of OTFTs is remarkably enhanced, such as the increase in charge carrier mobility from 0.56 to 1.05 cm2/Vs and the increase in on/off current ratio from 105–106 to 106–107. These results indicate that the dual interfacial modification of dielectrics is a simple and effective approach for the OTFT performance improvement.