Surface electronic properties of sulfur-treated GaAs determined by surface photovoltage measurement and its computer simulation

P. Tomkiewicz, S. Arabasz, B. Adamowicz, M. Miczek, J. Mizsei, D. R.T. Zahn, H. Hasegawa, J. Szuber

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The Kelvin method together with the simulations of surface photovoltage has been used to determine the surface electronic properties, i.e. the surface band bending (qVS), surface state density (NSS0) and surface fixed charge (QFx) of S2Cl2-treated GaAs (100) surfaces. The measured values of surface photovoltage (SPV) do not show saturation at high photon flux densities in contradiction to the simple theory of SPV. This behavior of SPV agrees very well with the rigorous computer simulations and can be explained in terms of the Dember effect. Moreover, the SPV values become insensitive to surface states at moderate photon flux densities. On this basis, the surface band bending of untreated (0.79 eV) and S2Cl2-treated (0.60 eV) GaAs surfaces was determined. The band diagrams summarizing the obtained results proved the influence on the potential variations not only from the ionized surface states and surface fixed charge but also from the surface dipole layer on the S2Cl2-treated GaAs surface. The dipole arises most probably due to the S-Ga bonding on the surface. The presented results offer an alternative explanation for increased PL commonly observed after the sulfidation in the absence of substantial reduction in the band bending.

Original languageEnglish
Pages (from-to)498-502
Number of pages5
JournalSurface Science
Issue number3
Publication statusPublished - Feb 1 2009



  • Contact potential
  • Fermi level pinning
  • GaAs
  • Kelvin probe
  • Passivation
  • SCl
  • Surface and interface states
  • Surface photovoltage

ASJC Scopus subject areas

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

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