Structural studies of sulfur-passivated GaAs (100) surfaces with LEED and AFM

Y. Ke, S. Milano, X. W. Wang, N. Tao, Y. Darici

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


We present the results of Auger electron spectroscopy (AES), low-energy electron diffraction (LEED) and atomic force microscopy (AFM) analysis of sulfur-passivating layers on the GaAs (100) surface. The GaAs surfaces were passivated with both inorganic [(NH4)2Sx] and organic [octadecylthiol (ODT)] S-based compounds. We prepared the inorganic sulfur-passivated GaAs(100) surfaces with a wet chemical treatment using (NH4)2S solution. This was followed by thermal annealing of the treated sample in an ultra-high vacuum (UHV). After ex-situ and in-situ treatments, the surface resulted in a (2 × 1) LEED pattern. The LEED data (I-E curves) were recorded and compared with dynamical LEED calculations for different structural models for the sulfur-passivated GaAs (100) surface. The results showed that the sulfur-passivated (2 × 1) surface structure is an arsenic-sulfur dimer on a Ga-terminated substrate. The ex-situ AFM results also revealed a (2 × 1) structure for the inorganic passivation and a very smooth surface for the organic ODT in the ethanol-treated sample.

Original languageEnglish (US)
Pages (from-to)29-36
Number of pages8
JournalSurface Science
Issue number1-2
StatePublished - Sep 30 1998
Externally publishedYes


  • Atomic force microscopy
  • Gallium arsenide
  • Low-energy electron diffraction
  • Roughness
  • Sulfur
  • Surface structure

ASJC Scopus subject areas

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


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