Scanning tunneling microscopy of passivated Au nanocrystals immobilized on Au(111) surfaces

L. E. Harrell, T. P. Bigioni, W. G. Cullen, R. L. Whetten, P. M. First

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


The surface mobility of alkanethiol-passivated Au nanocrystals on inert surfaces makes them challenging to image by scanning tunneling microscopy (STM). However, the potential for obtaining information on the density of states of these nanocrystals from tunneling spectroscopy measurements justifies the effort to find sample preparations that effectively immobilize them. We have explored the use of dithiol molecules as a means of strengthening the interaction between the substrate and the nanocrystal, with the goal of imaging isolated nanocrystals on a conducting substrate. Modifying the nanocrystals by substituting dithiol molecules into the passivation layer allowed the nanocrystals to bind strongly to the Au(111) surface. The formation of a self-assembled monolayer of xylenedithiol on the Au substrate allowed unmodified nanocrystals to more strongly adsorb to this modified surface. In both cases, isolated 1.7 nm nanocrystals were easily imaged by STM on Au(111), even at room temperature. These are significant steps toward the goal of obtaining high quality tunneling spectra from this class of materials.

Original languageEnglish (US)
Pages (from-to)2411-2416
Number of pages6
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Issue number6
StatePublished - 1999
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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