Modeling the electrical characteristics of TIPS-pentacene thin-film transistors: Effect of contact barrier, field-dependent mobility, and traps

Abstract

The device characteristics of organic thin-film transistors (OTFT) fabricated using tris-isopropylsilylethynyl (TIPS)-pentacene are analyzed with the help of a two-dimensional physics-based numerical simulation. The model incorporates contact barrier at a metal-semiconductor interface, field-dependent mobility, and trap distribution in TIPS-pentacene films and at dielectric-semiconductor interface. The Poole-Frenkel type field-dependence of mobility is included in addition to the contact barrier height of 0.38 eV to describe the non-ideal behavior in the linear region of the output characteristics. An account of the transfer characteristics and its hysteresis behavior is completed in both below- and above-threshold region upon consideration of the presence of acceptor-like traps of an exponential distribution in TIPS-pentacene films and positive trapped charges at dielectric-semiconductor interface. The obtained device parameters not only match the electrical characteristics but also give one an insight on the charge injection, transport, and trap properties of TIPS-pentacene from the perspectives of TFT operation. (C) 2008 Elsevier B.V. All rights reserved.