Charge transport across metal/molecular (alkyl) monolayer-Si junctions is dominated by the LUMO level

Omer Yaffe, Yabing Qi, Luc Scheres, Sreenivasa Reddy Puniredd, Lior Segev, Tal Ely, Hossam Haick, Han Zuilhof, Ayelet Vilan, Leeor Kronik, Antoine Kahn, David Cahen

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

We compare the charge transport characteristics of heavy-doped p ++- and n ++-Si-alkyl chain/Hg junctions. Based on negative differential resistance in an analogous semiconductor-inorganic insulator/metal junction we suggest that for both p ++- and n ++-type junctions, the energy difference between the Fermi level and lowest unoccupied molecular orbital (LUMO), i.e., electron tunneling, controls charge transport. This conclusion is supported by results from photoelectron spectroscopy (ultraviolet photoemission spectroscopy, inverse photoelectron spectroscopy, and x-ray photoemission spectroscopy) for the molecule-Si band alignment at equilibrium, which clearly indicate that the energy difference between the Fermi level and the LUMO is much smaller than that between the Fermi level and the highest occupied molecular orbital (HOMO). Furthermore, the experimentally determined Fermi level - LUMO energy difference, agrees with the non-resonant tunneling barrier height, deduced from the exponential length attenuation of the current.

Original languageEnglish (US)
Article number045433
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume85
Issue number4
DOIs
StatePublished - Jan 20 2012

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Fingerprint Dive into the research topics of 'Charge transport across metal/molecular (alkyl) monolayer-Si junctions is dominated by the LUMO level'. Together they form a unique fingerprint.

  • Cite this

    Yaffe, O., Qi, Y., Scheres, L., Puniredd, S. R., Segev, L., Ely, T., Haick, H., Zuilhof, H., Vilan, A., Kronik, L., Kahn, A., & Cahen, D. (2012). Charge transport across metal/molecular (alkyl) monolayer-Si junctions is dominated by the LUMO level. Physical Review B - Condensed Matter and Materials Physics, 85(4), [045433]. https://doi.org/10.1103/PhysRevB.85.045433