Energy-level alignment of a single molecule on ultrathin insulating film

Miyabi Imai-Imada, Hiroshi Imada, Kuniyuki Miwa, Jaehoon Jung, Tomoko Shimizu, Maki Kawai, Yousoo Kim

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Elucidation of the energy-level alignment mechanism at a molecule/insulator/metal interface is a key to understanding the molecular and interfacial phenomena. Herein, we provide a detailed investigation into the electronic structures of a free-base phthalocyanine on NaCl films of various thicknesses using scanning tunneling microscopy/spectroscopy (STM/STS). The energy of the ionization and the affinity levels of the molecule were deduced from the STS spectra, and we determined their dependence on the NaCl-film thickness, which can be explained based on three effects: a voltage drop within the NaCl films, the degree of electric-field screening around the molecule, and a variation in the work function of the substrates. We further found that the energy levels relative to the vacuum level are independent of the work function of the substrate, and that the size of the energy gap increases with the thickness. Our results suggest that it is possible to predict the energy levels at the interfaces based on the energy levels of the molecules in a gas phase, the work function of the substrate, and the thickness of the insulating films.

Original languageEnglish
Article number201403
JournalPhysical Review B
Volume98
Issue number20
DOIs
Publication statusPublished - 2018 Nov 15

Fingerprint

Electron energy levels
energy levels
alignment
Molecules
molecules
Substrates
space transportation system
Scanning tunneling microscopy
Ionization
Electronic structure
Film thickness
affinity
scanning tunneling microscopy
Screening
Energy gap
film thickness
screening
Gases
Metals
Electric fields

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Imai-Imada, M., Imada, H., Miwa, K., Jung, J., Shimizu, T., Kawai, M., & Kim, Y. (2018). Energy-level alignment of a single molecule on ultrathin insulating film. Physical Review B, 98(20), [201403]. https://doi.org/10.1103/PhysRevB.98.201403

Energy-level alignment of a single molecule on ultrathin insulating film. / Imai-Imada, Miyabi; Imada, Hiroshi; Miwa, Kuniyuki; Jung, Jaehoon; Shimizu, Tomoko; Kawai, Maki; Kim, Yousoo.

In: Physical Review B, Vol. 98, No. 20, 201403, 15.11.2018.

Research output: Contribution to journalArticle

Imai-Imada, M, Imada, H, Miwa, K, Jung, J, Shimizu, T, Kawai, M & Kim, Y 2018, 'Energy-level alignment of a single molecule on ultrathin insulating film', Physical Review B, vol. 98, no. 20, 201403. https://doi.org/10.1103/PhysRevB.98.201403
Imai-Imada, Miyabi ; Imada, Hiroshi ; Miwa, Kuniyuki ; Jung, Jaehoon ; Shimizu, Tomoko ; Kawai, Maki ; Kim, Yousoo. / Energy-level alignment of a single molecule on ultrathin insulating film. In: Physical Review B. 2018 ; Vol. 98, No. 20.
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