The emergence of transition metal dichalcogenides (TMDs) as 2D electronic materials has stimulated proposals of novel electronic and photonic devices based on TMD heterostructures. Here we report the determination of band offsets in TMD heterostructures by using microbeam X-ray photoelectron spectroscopy ({\mu}-XPS) and scanning tunneling microscopy/spectroscopy (STM/S). We determine a type-II alignment between MoS2 and WSe2 with a valence band offset (VBO) value of 0.83 eV and a conduction band offset (CBO) 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 VBO of 0.94 eV is obtained from density functional theory (DFT), consistent with the experimental determination.
@article{arxiv.1406.5137,
title = {Determination of band alignment in the single layer MoS2/WSe2 heterojunction},
author = {Ming-Hui Chiu and Chendong Zhang and Hung Wei Shiu and Chih-Piao Chuu and Chang-Hsiao Chen and Chih-Yuan S. Chang and Chia-Hao Chen and Mei-Yin Chou and Chih-Kang Shih and Lain-Jong Li},
journal= {arXiv preprint arXiv:1406.5137},
year = {2015}
}
Comments
^ These authors contributed equally. *Corresponding author E-mail: [email protected], [email protected] 20 pages, 4 figures in main text