Fabrication of Step-Edge Vertical-Channel Organic Transistors by Electro-Spray Deposition

Organic field-effect transistors (OFETs) have much attention for flexible, low cost, and ease of processing. The step-edge vertical-channel OFET (SVC-OFET) is one of vertical OFETs that can easily achieve a submicron channel using the step-edge structure [1]. On the other hand, the electrospray deposition (ESD) method is simple solution process used solution spray formed by electric field between the needle of syringe contained organic solution and conductive substrate or insulated electrode [2]. In this study, we fabricated SVC-OFETs based on 6,13-bis(triisopropyl-silylethynyl) pentacene (TIPS pentacene) as a semiconductor layer formed by ESD method. A schematic illustration of a SVC-FET is shown in Fig. 1. The sprayed solution accumulated and the organic semiconductor film was formed to cover around the gate electrode. Figure 2 shows the FET characteristics of TIPS pentacene with 1.0 wt% solution formed by ESD. The estimated carrier mobility was 4.0 × 10 cmVs. A part of this work was supported by New Energy and Industrial Technology Development Organization (NEDO). [1]T. Takano, et. al. : Appl.Phys.Express 2, 7 (2009) 071501. [2]T. Fukuda, et. al. : Thin Solid Films, 518 (2009) 575.