Printed Flexible Thin-Film Transistors

Abstract

The ability to realize flexible thin-film transistors (TFTs) which are key driving/switching components of wearable/stretchable electronics, offers much freedom on the target substrates. Therefore, a variety of functional materials focusing on semiconductors have been extensively explored for realizing competitive flexible TFTs, including traditional silicon, organics, and inorganics (such as oxides, carbon nanotubes (CNTs), graphene, and other emerging 2D materials). In particular, additive printing has great advantages for realizing stack-structured TFTs consisting of conductive, insulation, and semiconductor layers on flexible substrates with a low thermal budget, even below 200 °C when organic or nanoparticle-type functional inks are used. For obtaining high-performance printed TFTs, there is lots of research focused on printable semiconductor/dielectric/electrode materials, surface and interface properties, as well as printing techniques. With the in-depth research on materials, device structure, and manufacturing processes, TFTs gradually realize the fabrication on flexible substrates with printing techniques. This chapter will give a brief review on printed flexible thin-film transistors, including types of transistors, structure and operation of thin-film transistors, printing techniques and printed components of thin-film transistors, printed organic thin-film transistors, and printed inorganic thin-film transistors.KeywordsThin-film transistorOn–off ratioThreshold voltageTurn-on voltageSubthreshold swingEffective mobilityField-effect mobilitySaturation mobilityFlexible electrodeOxide transistor