Capacitance-voltage characteristics of MIS capacitors using polymeric insulators

Abstract

In this study, we investigate the capacitance-voltage (C-V) characteristics of metal-insulator-semiconductor (MIS) capacitors consisting of pentacene, as an organic semiconductor, and polymeric insulators such as poly(4-vinylphenol) (PVP) or polystyrene (PS) prepared by spin-coating process, to analyze the interfacial characteristics between pentacene and polymeric insulators. Compared with the device with PS, the MIS capacitor with PVP exhibited a pronounced shift in the flat-band voltage according to the bias sweep direction. This hysteric feature in the C-V characteristics is thought to be attributed to the trapped charges at the interface between pentacene and PVP owing to the hydrophilicity of PVP. From the experimental results, we can conclude that surface polarity of polymeric insulator has a critical effect on the interfacial properties, thereby affecting the bias stability of organic thin-film transistors. © 2008 Taylor & Francis Group, LLC.