title: Charge transport-driven selective oxidation of graphene.
abstract: Due to the tunability of the physical, electrical, and optical characteristics of graphene, precisely controlling graphene oxidation is of great importance for potential applications of graphene-based electronics. Here, we demonstrate a facile and precise way for graphene oxidation controlled by photoexcited charge transfer depending on the substrate and bias voltage. It is observed that graphene on TiO2 is easily oxidized under UV-ozone treatment, while graphene on SiO2 remains unchanged. The mechanism for the selective oxidation of graphene on TiO2 is associated with charge transfer from the TiO2 to the graphene. Raman spectra were used to investigate the graphene following applied bias voltages on the graphene/TiO2 diode under UV-ozone exposure. We found that under a reverse bias of 0.6 V on the graphene/TiO2 diode, graphene oxidation was accelerated under UV-ozone exposure, thus confirming the role of charge transfer between the graphene and the TiO2 that results in the selective oxidation of the graphene. The selective oxidation of graphene can be utilized for the precise, nanoscale patterning of the graphene oxide and locally patterned chemical doping, finally leading to the feasibility and expansion of a variety of graphene-based applications.
authors.affiliation: Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea. jeongypark@kaist.ac.kr and Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Young Keun
authors.initials: YK
authors.lastname: Lee
authors.affiliation: Creative Research Center for Graphene Electronics, ETRI (Electronics and Telecommunications Research Institute), Gajeongno, Yuseong-gu, Daejeon, 305-700, Republic of Korea.
authors.forename: Hongkyw
authors.initials: H
authors.lastname: Choi
authors.affiliation: Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea. jeongypark@kaist.ac.kr and Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Changhwan
authors.initials: C
authors.lastname: Lee
authors.affiliation: Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea. jeongypark@kaist.ac.kr and Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Hyunsoo
authors.initials: H
authors.lastname: Lee
authors.affiliation: Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea. jeongypark@kaist.ac.kr and Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Kalyan C
authors.initials: KC
authors.lastname: Goddeti
authors.affiliation: Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea. jeongypark@kaist.ac.kr and Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Song Yi
authors.initials: SY
authors.lastname: Moon
authors.affiliation: Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea. jeongypark@kaist.ac.kr and Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Won Hui
authors.initials: WH
authors.lastname: Doh
authors.affiliation: Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Jaeyoon
authors.initials: J
authors.lastname: Baik
authors.affiliation: Creative Research Center for Graphene Electronics, ETRI (Electronics and Telecommunications Research Institute), Gajeongno, Yuseong-gu, Daejeon, 305-700, Republic of Korea.
authors.forename: Jin-Soo
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Creative Research Center for Graphene Electronics, ETRI (Electronics and Telecommunications Research Institute), Gajeongno, Yuseong-gu, Daejeon, 305-700, Republic of Korea.
authors.forename: Jin Sik
authors.initials: JS
authors.lastname: Choi
authors.affiliation: Creative Research Center for Graphene Electronics, ETRI (Electronics and Telecommunications Research Institute), Gajeongno, Yuseong-gu, Daejeon, 305-700, Republic of Korea.
authors.forename: Choon-Gi
authors.initials: CG
authors.lastname: Choi
authors.affiliation: Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Daejeon 305-701, Korea. jeongypark@kaist.ac.kr and Graduate School of EEWS, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 305-701, Korea.
authors.forename: Jeong Young
authors.initials: JY
authors.lastname: Park