Dynamical low-energy electron-diffraction analysis of bismuth and antimony epitaxy on GaAs(110).

Abstract

The atomic geometry of Bi adsorbed on GaAs(110) is determined using low-energy electron diffraction (LEED) and compared with calculated atomic geometries of GaAs(111)-p(1\ifmmode\times\else\texttimes\fi{}1)-Sb and clean GaAs(110). The analysis of the one-monolayer, epitaxical films is facilitated by comparing LEED intensity data measured for each system under identical experimental conditions and analyzed using a common multiple-scattering model. The overlapping chain geometry, recently proposed as a possible alternative to the previously determined geometry for the GaAs(110)-p(1\ifmmode\times\else\texttimes\fi{}1)-Sb system, was tested for both the Sb and Bi systems. Comprehensive multiple-scattering calculations indicate, however, that the previously determined geometry provides the superior fit to the LEED intensity measurements. Several improvements to the LEED analysis methodology, including simultaneous multidimensional optimization, are described.