Inter-Layer Coupling Induced Valence Band Edge Shift in Mono- to Few-Layer MoS 2

Daniel J. Trainer, Aleksei V. Putilov, Cinzia Di Giorgio, Timo Saari, Baokai Wang, Mattheus Wolak, Ravini U. Chandrasena, Christopher Lane, Tay Rong Chang, Horng Tay Jeng, Hsin Lin, Florian Kronast, Alexander X. Gray, Xiaoxing X. Xi, Jouko Nieminen, Arun Bansil, Maria Iavarone

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)

Abstract

Recent progress in the synthesis of monolayer MoS 2, a two-dimensional direct band-gap semiconductor, is paving new pathways toward atomically thin electronics. Despite the large amount of literature, fundamental gaps remain in understanding electronic properties at the nanoscale. Here, we report a study of highly crystalline islands of MoS 2 grown via a refined chemical vapor deposition synthesis technique. Using high resolution scanning tunneling microscopy and spectroscopy (STM/STS), photoemission electron microscopy/spectroscopy (PEEM) and μ-ARPES we investigate the electronic properties of MoS 2 as a function of the number of layers at the nanoscale and show in-depth how the band gap is affected by a shift of the valence band edge as a function of the layer number. Green's function based electronic structure calculations were carried out in order to shed light on the mechanism underlying the observed bandgap reduction with increasing thickness, and the role of the interfacial Sulphur atoms is clarified. Our study, which gives new insight into the variation of electronic properties of MoS 2 films with thickness bears directly on junction properties of MoS 2, and thus impacts electronics application of MoS 2.

Original languageEnglish
Article number40559
JournalScientific reports
Volume7
DOIs
Publication statusPublished - 2017 Jan 13

All Science Journal Classification (ASJC) codes

  • General

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