title: High-performance solution-processed amorphous zinc-indium-tin oxide thin-film transistors.
abstract: Films of the high-performance solution-processed amorphous oxide semiconductor a-ZnIn(4)Sn(4)O(15), grown from 2-methoxyethanol/ethanolamine solutions, were used to fabricate thin-film transistors (TFTs) in combination with an organic self-assembled nanodielectric as the gate insulator. This structurally dense-packed semiconductor composition with minimal Zn(2+) incorporation strongly suppresses transistor off-currents without significant mobility degradation, and affords field-effect electron mobilities of approximately 90 cm(2) V(-1) s(-1) (104 cm(2) V(-1) s(-1) maximum obtained for patterned ZITO films), with I(on)/I(off) ratio approximately 10(5), a subthreshhold swing of approximately 0.2 V/dec, and operating voltage <2 V for patterned devices with W/L = 50. The microstructural and electronic properties of ZITO semiconductor film compositions in the range Zn(9-2x)In(x)Sn(x)O(9+1.5x) (x = 1-4) and ZnIn(8-x)Sn(x)O(13+0.5x) (x = 1-7) were systematically investigated to elucidate those factors which yield optimum mobility, I(on)/I(off), and threshold voltage parameters. It is shown that structural relaxation and densification by In(3+) and Sn(4+) mixing is effective in reducing carrier trap sites and in creating carrier-generating oxygen vacancies. In contrast to the above results for TFTs fabricated with the organic self-assembled nanodielectric, ZnIn(4)Sn(4)O(15) TFTs fabricated with SiO(2) gate insulators exhibit electron mobilities of only approximately 11 cm(2) V(-1) s(-1) with I(on)/I(off) ratios approximately 10(5), and a subthreshhold swing of approximately 9.5 V/dec.
authors.affiliation: Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA.
authors.forename: Myung-Gil
authors.initials: MG
authors.lastname: Kim
authors.forename: Hyun Sung
authors.initials: HS
authors.lastname: Kim
authors.forename: Young-Geun
authors.initials: YG
authors.lastname: Ha
authors.forename: Jiaqing
authors.initials: J
authors.lastname: He
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis
authors.forename: Antonio
authors.initials: A
authors.lastname: Facchetti
authors.forename: Tobin J
authors.initials: TJ
authors.lastname: Marks