Lightweight flexible indium-free oxide TFTs with AND logic function employing chitosan biopolymer as self-supporting layer

Abstract

Chitosan, a natural polysaccharide, is nontoxic, lightweight and biodegradable, which exhibits a great potential for the emerging flexible and “green” electronic applications. Here, lightweight flexible aluminum-zinc-oxide (AZO) thin-film transistors (TFTs) are fabricated using chitosan biopolymer as self-supporting layer. This kind of biopolymer electrolyte can provide a strong electric-double-layer effect, which leads to a large capacitance with lower energy consumption. With the low-cost indium-free AZO deposited onto the chitosan film as the coplanar gate and source/channel/drain electrodes, the transistor shows a moderate on/off ratio of ∼104, a relatively ideal field-effect mobility of 0.3 cm2/Vs and a moderate sub-threshold swing of 0.65 V/dec. Moreover, logic “AND” function is realized in the flexible device with two coplanar gates as the input terminals. Such chitosan-gated flexible TFT devices can provide promising candidates for the next generation wearable and “green” electronics.