Nitroxyl free radical binding to Si(1 0 0): A combined scanning tunneling microscopy and computational modeling study

Mark E. Greene*, Nathan P. Guisinger, Rajiv Basu, Andrew S. Baluch, Mark C. Hersam

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

22 Scopus citations


The ultra-high vacuum scanning tunneling microscope (UHV-STM) was used to investigate the addition of the 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) radical to the Si(1 0 0) surface. Room temperature studies performed on clean Si(1 0 0)-2×1 confirm the proposed binding of the unpaired valence electron associated with the singly occupied molecular orbital (SOMO) of the molecule with a Si dangling bond. A strong bias dependence in the topography of isolated molecules was observed in the range of -2.0 to +2.5 V. Semiempirical and density functional calculations of TEMPO bound to a three-dimer silicon cluster model yield occupied state density isosurfaces below the highest occupied (HOMO) and unoccupied state densities isosurfaces above the lowest unoccupied molecular orbital (LUMO) which trend in qualitative agreement with the bias dependent STM topography. Furthermore, the placement of TEMPO molecules on dangling bonds was controlled with atomic precision on the monohydride Si(1 0 0) surface via electron stimulated desorption of H, demonstrating the compatibility of nitroxyl free radical binding chemistries with nanopatterning techniques such as feedback controlled lithography.

Original languageEnglish (US)
Pages (from-to)16-28
Number of pages13
JournalSurface Science
Issue number1
StatePublished - Jun 10 2004


  • Density functional calculations
  • Molecule-solid reactions
  • Scanning tunneling microscopy
  • Silicon
  • Surface electronic phenomena (work function, surface potential, surface states, etc.)

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry


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