Solution Processed High-k/Low-k Bilayer Gate Dielectrics for Flexible Organic Transistors

Abstract

In this paper, a bi-layer combination of high-k/low-k gate dielectric consisting of poly (vinyl alcohol) (PVA) and poly (4-vinylphenol-co-methyl methacrylate) (PVP-Co-PMMA) polymers was explored to fabricate high performance flexible organic transistors. Solution processed TIPS-Pentacene: polystyrene (PS) was used to demonstrate p-channel transistors with excellent electrical characteristics. These devices exhibited average and maximum field-effect mobility (μ) values of ~0.2 (±0.1) cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">^</sup> 2/Vs and ~0.5 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">^</sup> 2/V s in the saturation regime with high current (I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</inf> /I <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</inf> ) ratio of ~10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">^</sup> 4 at an operating voltage of -8 V, with negligible hysteresis in transfer curves. Moreover, excellent repeatability in electrical characteristics with high cyclic and bias stress stability were also achieved. These findings suggest that this unique bi-layer gate dielectric combination can act as an excellent alternative for solution processed organic transistors.