Jung-Hun Noh

Fully Flexible Solution‐Deposited ZnO Thin‐Film Transistors

Electronic systems on fl exible substrates posses the advantage of mechanical fl exibility in actual use, but also provide more rugged rollable devices and may therefore result in lower manufacturing costs associated with continuous roll-to-roll fabrication. To realize these advantages of fl exible electronics, lowtemperature solution processing is strongly desirable. In this regard, organic semiconductor materials have been extensively researched. [ 1 ] Organic semiconductor polymers are soluble in a variety of solvents, and small molecules can be derivatized to soluble precursors. Organic transistors can also be fabricated by solution processing near room temperature, [ 2 ] compatible with temperature-sensitive plastic substrates. [ 3–5 ] Despite successful demonstrations of fl exible organic electronics, however, they are generally sensitive to operating conditions and are unstable during long-term operation. [ 6 ]

Low-Temperature Solution-Deposited Oxide Thin-Film Transistors Based on Solution-Processed Organic–Inorganic Hybrid Dielectrics

We describe low-temperature, solution-deposited, oxide semiconductor thin-film transistors (TFTs) with a solution-processed gate dielectric in this study. The sol–gel-derived indium zinc oxide (IZO) semiconductor matched well with the organic–inorganic hybrid dielectric annealed at 200 °C, forming a coherent interface between the semiconductor and the dielectric without evidence of chemical damage. The IZO-TFTs made with a 420-nm-thick hybrid dielectric layer showed good performance: a low off-current on the order of <10-10 A, a field-effect mobility of 3.3×10-2 cm2 V-1 s-1, and a low threshold gate voltage of ~2.4 V. Spin-coating of the IZO semiconductor on a hybrid dielectric/glass substrate results in TFTs optically transparent in the entire visible region (~90%). Our solution-processable materials of the semiconductor and the gate dielectric can open the possibility of realizing flexible transparent devices using all-solution processing.