Phys. Rev. B 58 (1998) 13820-13823
Structure of the Cl-passivated GaAs(111) surface
Z.H. Lu
Institute for Microstructural Sciences, National Research Council of Canada, Ottawa, Canada K1A 0R6
T. Tyliszczak and A.P. Hitchcock
Institute for Materials Research, McMaster University, Hamilton, Ont., Canada L8S 4M1


Cl 1s (K-shell) near-edge and extended X-ray absorption fine structure spectroscopy has been used to study the chemistry and structure of the Cl passivated GaAs(111) surface. The Cl passivation is achieved in ambient atmosphere by wet chemical methods. It is found that Cl forms a stable monochloride structure with Cl bonded to Ga. Strong polarization dependence was observed both in the Cl 1s ® 3p s -resonance and in the extended fine structure region. Quantitative analysis, including numerical calculations using the multiple scattering method on an 85-atom cluster, show that the Ga-Cl bond is oriented along the <111> surface normal with a Ga-Cl bond length of 2.17±0.02 Å.