title: Large Work Function Modulation of Monolayer MoS2 by Ambient Gases.
abstract: Although two-dimensional monolayer transition-metal dichalcogenides reveal numerous unique features that are inaccessible in bulk materials, their intrinsic properties are often obscured by environmental effects. Among them, work function, which is the energy required to extract an electron from a material to vacuum, is one critical parameter in electronic/optoelectronic devices. Here, we report a large work function modulation in MoS2 via ambient gases. The work function was measured by an in situ Kelvin probe technique and further confirmed by ultraviolet photoemission spectroscopy and theoretical calculations. A measured work function of 4.04 eV in vacuum was converted to 4.47 eV with O2 exposure, which is comparable with a large variation in graphene. The homojunction diode by partially passivating a transistor reveals an ideal junction with an ideality factor of almost one and perfect electrical reversibility. The estimated depletion width obtained from photocurrent mapping was ∼200 nm, which is much narrower than bulk semiconductors.
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Si Young
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Un Jeong
authors.initials: UJ
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: JaeGwan
authors.initials: J
authors.lastname: Chung
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Honggi
authors.initials: H
authors.lastname: Nam
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Hye Yun
authors.initials: HY
authors.lastname: Jeong
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Gang Hee
authors.initials: GH
authors.lastname: Han
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Hyun
authors.initials: H
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Hye Min
authors.initials: HM
authors.lastname: Oh
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Hyangsook
authors.initials: H
authors.lastname: Lee
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Hyochul
authors.initials: H
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Young-Geun
authors.initials: YG
authors.lastname: Roh
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Jineun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Hwang
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Yeonsang
authors.initials: Y
authors.lastname: Park
authors.affiliation: Center for Integrated Nanostructure Physics (CINAP), Institute for Basic Science (IBS), and ‡Department of Energy Science, Department of Physics, Sungkyunkwan University , Suwon 440-746, Republic of Korea.|Device Laboratory and ∥AE group, Platform Technology Laboratory, Samsung Advanced Institute of Technology , Suwon 443-803, Republic of Korea.
authors.forename: Young Hee
authors.initials: YH
authors.lastname: Lee
keywords: Kelvin probe; diode; monolayer MoS2; photocurrent; work function