title: Aqueous inorganic inks for low-temperature fabrication of ZnO TFTs.
abstract: A simple, low-cost, and nontoxic aqueous ink chemistry is described for digital printing of ZnO films. Selective design through controlled precipitation, purification, and dissolution affords an aqueous Zn(OH)(x)(NH(3))(y)((2-x)+) solution that is stable in storage, yet promptly decomposes at temperatures below 150 degrees C to form wurtzite ZnO. Dense, high-quality, polycrystalline ZnO films are deposited by ink-jet printing and spin-coating, and film structure is elucidated via X-ray diffraction and electron microscopy. Semiconductor film functionality and quality are examined through integration in bottom-gate thin-film transistors. Enhancement-mode TFTs with ink-jet printed ZnO channels annealed at 300 degrees C are found to exhibit strong field effect and excellent current saturation in tandem with incremental mobilities from 4-6 cm(2) V(-1) s(-1). Spin-coated ZnO semiconductors processed at 150 degrees C are integrated with solution-deposited aluminum oxide phosphate dielectrics in functional transistors, demonstrating both high performance, i.e., mobilities up to 1.8 cm(2) V(-1) s(-1), and the potential for low-temperature solution processing of all-oxide electronics.
authors.affiliation: Department of Chemistry, Oregon State University, 153 Gilbert Hall, Corvallis, Oregon 97331-4003, USA.
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Meyers
authors.forename: Jeremy T
authors.initials: JT
authors.lastname: Anderson
authors.forename: Celia M
authors.initials: CM
authors.lastname: Hung
authors.forename: John
authors.initials: J
authors.lastname: Thompson
authors.forename: John F
authors.initials: JF
authors.lastname: Wager
authors.forename: Douglas A
authors.initials: DA
authors.lastname: Keszler