Effect of molecular binding to a semiconductor on metal/molecule/ semiconductor junction behavior

Hossam Haick, Jamal Ghabboun, Olivia Niitsoo, Hagai Cohen, David Cahen, Ayelet Vilan, Jaehyung Hwang, Alan Wan, Fabrice Amy, Antoine Kahn

Research output: Contribution to journalArticlepeer-review

35 Scopus citations


Diodes made by (indirectly) evaporating Au on a monolayer of molecules that are adsorbed chemically onto GaAs, via either disulfide or dicarboxylate groups, show roughly linear but opposite dependence of their effective barrier height on the dipole moment of the molecules. We explain this by Au-molecule (electrical) interactions not only with the exposed end groups of the molecule but also with its binding groups. We arrive at this conclusion by characterizing the interface by in situ UPS-XPS, ex situ XPS, TOF-SIMS, and Kelvin probe measurements, by scanning microscopy of the surfaces, and by current-voltage measurements of the devices. While there is a very limited interaction of Au with the dicarboxylic binding groups, there is a much stronger interaction with the disulfide groups. We suggest that these very different interactions lead to different (growth) morphologies of the evaporated gold layer, resulting in opposite effects of the molecular dipole on the junction barrier height.

Original languageEnglish (US)
Pages (from-to)9622-9630
Number of pages9
JournalJournal of Physical Chemistry B
Issue number19
StatePublished - May 19 2005

All Science Journal Classification (ASJC) codes

  • Materials Chemistry
  • Surfaces, Coatings and Films
  • Physical and Theoretical Chemistry


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