title: Improvement of Electrical Characteristics and Stability of Amorphous Indium Gallium Zinc Oxide Thin Film Transistors Using Nitrocellulose Passivation Layer.
abstract: In this research, nitrocellulose is proposed as a new material for the passivation layers of amorphous indium gallium zinc oxide thin film transistors (a-IGZO TFTs). The a-IGZO TFTs with nitrocellulose passivation layers (NC-PVLs) demonstrate improved electrical characteristics and stability. The a-IGZO TFTs with NC-PVLs exhibit improvements in field-effect mobility (μFE) from 11.72 ± 1.14 to 20.68 ± 1.94 cm2/(V s), threshold voltage (Vth) from 1.85 ± 1.19 to 0.56 ± 0.35 V, and on/off current ratio (Ion/off) from (5.31 ± 2.19) × 107to (4.79 ± 1.54) × 108compared to a-IGZO TFTs without PVLs, respectively. The Vthshifts of a-IGZO TFTs without PVLs, with poly(methyl methacrylate) (PMMA) PVLs, and with NC-PVLs under positive bias stress (PBS) test for 10,000 s represented 5.08, 3.94, and 2.35 V, respectively. These improvements were induced by nitrogen diffusion from NC-PVLs to a-IGZO TFTs. The lone-pair electrons of diffused nitrogen attract weakly bonded oxygen serving as defect sites in a-IGZO TFTs. Consequently, the electrical characteristics are improved by an increase of carrier concentration in a-IGZO TFTs, and a decrease of defects in the back channel layer. Also, NC-PVLs have an excellent property as a barrier against ambient gases. Therefore, the NC-PVL is a promising passivation layer for next-generation display devices that simultaneously can improve electrical characteristics and stability against ambient gases.
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Kwan Yup
authors.initials: KY
authors.lastname: Shin
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Young Jun
authors.initials: YJ
authors.lastname: Tak
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Won-Gi
authors.initials: WG
authors.lastname: Kim
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Seonghwan
authors.initials: S
authors.lastname: Hong
authors.affiliation: School of Electrical and Electronic Engineering, Yonsei University , 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Hyun Jae
authors.identifier: http://orcid.org/0000-0002-6727-014X
authors.initials: HJ
authors.lastname: Kim
keywords: a-IGZO; nitrocellulose; oxide semiconductor; passivation; thin-film transistors