Ionic self-assembled monolayer for low contact resistance in inkjet-printed coplanar structure organic thin-film transistors

Abstract To reduce the contact resistance in inkjet-printed organic thin-film transistors (OTFTs), the use of a newly synthesized ionic self-assembled monolayer (SAM) consisting of an anchoring group, a linker group, and an ionic functional group, is investigated. According to the gated transmission line method (TLM) measurements of a series of OTFT devices, where one type has no charge injection layer, another type having a pentafluorobenzenethiol (PFBT) injection layer, and a third type containing a (6-mercaptohexyl)trimethylammonium bromide (MTAB) ionic SAM, the latter exhibits the lowest contact resistance value of ∼3.1 K Ω cm. The OTFTs without charge injection layer and with the PFBT SAM have relatively higher contact resistance values of ∼6.4 K Ω cm and ∼5.0 K Ω cm, respectively. The reduced contact resistance in the OTFTs with ionic SAMs is attributed to the large charge carrier density induced by the ionic SAM, which allows sufficient tunneling-assisted injection of the carriers from the metal electrode to the polymer semiconductor. These results suggest that the use of appropriate ionic SAM injection layer is an effective way to reduce the contact resistance, hence improving the charge transport characteristics of inkjet-printed OTFTs.

[1]  Gilles Horowitz,et al.  Organic thin film transistors: From theory to real devices , 2004 .

[2]  B. Henrissat,et al.  Dynamic Light Scattering Evidence for a Ligand-Induced Motion between the Two Domains of Glucoamylase G1 of Aspergillus niger with Heterobivalent Substrate Analogues. , 1999, Angewandte Chemie.

[3]  S. M. Sze,et al.  Physics of semiconductor devices , 1969 .

[4]  Yanli Liu,et al.  Synthesis, stability, and cellular internalization of gold nanoparticles containing mixed peptide-poly(ethylene glycol) monolayers. , 2007, Analytical chemistry.

[5]  Hagen Klauk,et al.  Organic thin-film transistors. , 2010, Chemical Society reviews.

[6]  Takao Someya,et al.  Flexible low-voltage organic thin-film transistors and circuits based on C10-DNTT , 2012 .

[7]  Eugenio Cantatore,et al.  Applications of organic and printed electronics : a technology-enabled revolution , 2013 .

[8]  Barbara Stadlober,et al.  Orders‐of‐Magnitude Reduction of the Contact Resistance in Short‐Channel Hot Embossed Organic Thin Film Transistors by Oxidative Treatment of Au‐Electrodes , 2007 .

[9]  John E. Anthony,et al.  High-mobility spin-cast organic thin film transistors , 2008 .

[10]  C. Goss,et al.  Application of (3-mercaptopropyl)trimethoxysilane as a molecular adhesive in the fabrication of vapor-deposited gold electrodes on glass substrates , 1991 .

[11]  R. Muller,et al.  High mobility short-channel p-type organic transistors with reduced gold content and completely gold-free source/drain bottom contacts , 2011 .

[12]  Yong-Young Noh,et al.  Downscaling of self-aligned, all-printed polymer thin-film transistors. , 2007, Nature nanotechnology.

[13]  Chieh-Wei Chen,et al.  High-performance organic thin-film transistors with metal oxide/metal bilayer electrode , 2005 .

[14]  S. Rhee,et al.  Metal–semiconductor contact in organic thin film transistors , 2008 .

[15]  Jihoon Park,et al.  Flexible semitransparent pentacene thin-film transistors with polymer dielectric layers and NiOx electrodes , 2005 .

[16]  Jae Eun Jang,et al.  Reliable and Uniform Thin‐Film Transistor Arrays Based on Inkjet‐Printed Polymer Semiconductors for Full Color Reflective Displays , 2013, Advanced materials.

[17]  Mario Caironi,et al.  Charge Injection in Solution‐Processed Organic Field‐Effect Transistors: Physics, Models and Characterization Methods , 2012, Advanced materials.

[18]  Paul Heremans,et al.  Organic Transistors in Optical Displays and Microelectronic Applications , 2010, Advanced materials.

[19]  C. Chien,et al.  Improving Electrical Properties of Bottom-Gate Poly(3-Hexylthiophene) Thin-Film Transistor Using $\hbox{CF}_{4}$ Plasma Treatment , 2013, IEEE Electron Device Letters.

[20]  P. Heremans,et al.  Analog Organic Electronics: Building Blocks for Organic Smart Sensor Systems on Foil , 2012 .

[21]  Kazuhito Tsukagoshi,et al.  Current transport in short channel top-contact pentacene field-effect transistors investigated with the selective molecular doping technique , 2007 .

[22]  T. Jackson,et al.  Pentacene TFT with improved linear region characteristics using chemically modified source and drain electrodes , 2001, IEEE Electron Device Letters.

[23]  Christophe Serbutoviez,et al.  Modification of gold source and drain electrodes by self-assembled monolayer in staggered n- and p-channel organic thin film transistors , 2010 .