title: Determination of band alignment in the single-layer MoS2/WSe2 heterojunction.
abstract: The emergence of two-dimensional electronic materials has stimulated proposals of novel electronic and photonic devices based on the heterostructures of transition metal dichalcogenides. Here we report the determination of band offsets in the heterostructures of transition metal dichalcogenides by using microbeam X-ray photoelectron spectroscopy and scanning tunnelling microscopy/spectroscopy. We determine a type-II alignment between MoS2 and WSe2 with a valence band offset value of 0.83 eV and a conduction band offset of 0.76 eV. First-principles calculations show that in this heterostructure with dissimilar chalcogen atoms, the electronic structures of WSe2 and MoS2 are well retained in their respective layers due to a weak interlayer coupling. Moreover, a valence band offset of 0.94 eV is obtained from density functional theory, consistent with the experimental determination.
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan.
authors.forename: Ming-Hui
authors.initials: MH
authors.lastname: Chiu
authors.affiliation: Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Chendong
authors.initials: C
authors.lastname: Zhang
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Hung-Wei
authors.initials: HW
authors.lastname: Shiu
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan.
authors.forename: Chih-Piao
authors.initials: CP
authors.lastname: Chuu
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan.
authors.forename: Chang-Hsiao
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan.
authors.forename: Chih-Yuan S
authors.initials: CY
authors.lastname: Chang
authors.affiliation: National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan.
authors.forename: Chia-Hao
authors.initials: CH
authors.lastname: Chen
authors.affiliation: 1] Institute of Atomic and Molecular Sciences, Academia Sinica, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan. [2] School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA. [3] Deapartment of Physics, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Mei-Yin
authors.initials: MY
authors.lastname: Chou
authors.affiliation: Department of Physics, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Chih-Kang
authors.initials: CK
authors.lastname: Shih
authors.affiliation: 1] Institute of Atomic and Molecular Sciences, Academia Sinica, No. 1, Roosevelt Road, Sec. 4, Taipei 10617, Taiwan. [2] Physical Sciences and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Kingdom of Saudi Arabia.
authors.forename: Lain-Jong
authors.initials: LJ
authors.lastname: Li