title: Photochemical Hydrogen Doping Induced Embedded Two-Dimensional Metallic Channel Formation in InGaZnO at Room Temperature.
abstract: The photochemical tunability of the charge-transport mechanism in metal-oxide semiconductors is of great interest since it may offer a facile but effective semiconductor-to-metal transition, which results from photochemically modified electronic structures for various oxide-based device applications. This might provide a feasible hydrogen (H)-radical doping to realize the effectively H-doped metal oxides, which has not been achieved by thermal and ion-implantation technique in a reliable and controllable way. In this study, we report a photochemical conversion of InGaZnO (IGZO) semiconductor to a transparent conductor via hydrogen doping to the local nanocrystallites formed at the IGZO/glass interface at room temperature. In contrast to thermal or ionic hydrogen doping, ultraviolet exposure of the IGZO surface promotes a photochemical reaction with H radical incorporation to surface metal-OH layer formation and bulk H-doping which acts as a tunable and stable highly doped n-type doping channel and turns IGZO to a transparent conductor. This results in the total conversion of carrier conduction property to the level of metallic conduction with sheet resistance of ∼16 Ω/□, room temperature Hall mobility of 11.8 cm(2) V(-1) sec(-1), the carrier concentration at ∼10(20) cm(-3) without any loss of optical transparency. We demonstrated successful applications of photochemically highly n-doped metal oxide via optical dose control to transparent conductor with excellent chemical and optical doping stability.
authors.affiliation: Division of Materials Science and Engineering, Hanyang University , Seoul 133-791, Republic of Korea.
authors.forename: Myeong-Ho
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Department of Energy Systems Research & Department of Materials Science and Engineering, Ajou University , Suwon 443-739, Republic of Korea.
authors.forename: Young-Ahn
authors.initials: YA
authors.lastname: Lee
authors.affiliation: Department of Energy Systems Research & Department of Materials Science and Engineering, Ajou University , Suwon 443-739, Republic of Korea.
authors.forename: Jinseo
authors.initials: J
authors.lastname: Kim
authors.affiliation: Gyeongbuk Science Technology Promotion Center, Gumi Electronics & Information Technology Research Institute , Gumi 730-853, Gyeongbuk Republic of Korea.
authors.forename: Jucheol
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Environmental Engineering, Inha University , Incheon 402-751, Republic of Korea.
authors.forename: Seungbae
authors.initials: S
authors.lastname: Ahn
authors.affiliation: Department of Environmental Engineering, Inha University , Incheon 402-751, Republic of Korea.
authors.forename: Ki-Joon
authors.initials: KJ
authors.lastname: Jeon
authors.affiliation: Korea Research Institute of Standards and Science , Daejeon 305-340, Republic of Korea.
authors.forename: Jeong Won
authors.initials: JW
authors.lastname: Kim
authors.affiliation: Division of Materials Science and Engineering, Hanyang University , Seoul 133-791, Republic of Korea.
authors.forename: Duck-Kyun
authors.initials: DK
authors.lastname: Choi
authors.affiliation: Department of Energy Systems Research & Department of Materials Science and Engineering, Ajou University , Suwon 443-739, Republic of Korea.
authors.forename: Hyungtak
authors.initials: H
authors.lastname: Seo
keywords: 2 DEG; IGZO; hydrogen doping; metallic conduction; photochemistry