Tunable Bandgap Narrowing Induced by Controlled Molecular Thickness in 2D Mica Nanosheets

Sang Sub Kim, Tran Van Khai, Vadym Kulish, Yoon Hyun Kim, Han Gil Na, Akash Katoch, Minoru Osada, Ping Wu, Hyoun Woo Kim

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    15 Citations (Scopus)

    Abstract

    Bandgap engineering of atomically thin 2D crystals is critical for their applications in nanoelectronics, optoelectronics, and photonics. Here, we report a simple but rather unexpected approach for bandgap engineering of muscovite-type mica nanosheets (KAl<inf>3</inf>Si<inf>3</inf>O<inf>10</inf>(OH)<inf>2</inf>) via controlled molecular thickness. Through density functional calculations, we analyze electronic structures in 2D mica nanosheets and develop a general picture for tunable bandgap narrowing induced by controlled molecular thickness. From conducting atomic force microscopy, we observe an abnormal bandgap narrowing in 2D mica nanosheets, contrary to well-known quantum size effects. In mica nanosheets, decreasing the number of layers results in reduced bandgap energy from 7 to 2.5 eV, and the bilayer case exhibits a semiconducting nature with -2.5 eV. Structural modeling by transmission electron microscopy and density functional calculations reveal that this bandgap narrowing can be defined as a consequence of lattice relaxations as well as surface doping effects. These bandgap engineered 2D mica nanosheets open up an exciting opportunity for new physical properties in 2D materials and may find diverse applications in 2D electronic/optoelectronic devices.

    Original languageEnglish
    Pages (from-to)4222-4228
    Number of pages7
    JournalChemistry of Materials
    Volume27
    Issue number12
    DOIs
    Publication statusPublished - 2015 Jun 23

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    ASJC Scopus subject areas

    • Materials Chemistry
    • Chemical Engineering(all)
    • Chemistry(all)

    Cite this

    Kim, S. S., Khai, T. V., Kulish, V., Kim, Y. H., Na, H. G., Katoch, A., Osada, M., Wu, P., & Kim, H. W. (2015). Tunable Bandgap Narrowing Induced by Controlled Molecular Thickness in 2D Mica Nanosheets. Chemistry of Materials, 27(12), 4222-4228. https://doi.org/10.1021/cm504802j