Interlayer orientation-dependent light absorption and emission in monolayer semiconductor stacks

Hoseok Heo, Ji Ho Sung, Soonyoung Cha, Bo Gyu Jang, Joo Youn Kim, Gangtae Jin, Donghun Lee, Ji Hoon Ahn, Myoung Jae Lee, Ji Hoon Shim, Hyunyong Choi, Moon Ho Jo

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Abstract

Two-dimensional stacks of dissimilar hexagonal monolayers exhibit unusual electronic, photonic and photovoltaic responses that arise from substantial interlayer excitations. Interband excitation phenomena in individual hexagonal monolayer occur in states at band edges (valleys) in the hexagonal momentum space; therefore, low-energy interlayer excitation in the hexagonal monolayer stacks can be directed by the two-dimensional rotational degree of each monolayer crystal. However, this rotation-dependent excitation is largely unknown, due to lack in control over the relative monolayer rotations, thereby leading to momentum-mismatched interlayer excitations. Here, we report that light absorption and emission in MoS 2/WS 2 monolayer stacks can be tunable from indirect-to direct-gap transitions in both spectral and dynamic characteristics, when the constituent monolayer crystals are coherently stacked without in-plane rotation misfit. Our study suggests that the interlayer rotational attributes determine tunable interlayer excitation as a new set of basis for investigating optical phenomena in a two-dimensional hexagonal monolayer system.

Original languageEnglish
Article number7372
JournalNature communications
Volume6
DOIs
Publication statusPublished - 2015 Jun 23

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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    Heo, H., Sung, J. H., Cha, S., Jang, B. G., Kim, J. Y., Jin, G., Lee, D., Ahn, J. H., Lee, M. J., Shim, J. H., Choi, H., & Jo, M. H. (2015). Interlayer orientation-dependent light absorption and emission in monolayer semiconductor stacks. Nature communications, 6, [7372]. https://doi.org/10.1038/ncomms8372