Structure and surface core level shifts of the GaAs(114)A and B surfaces

Abstract

The structure and electronic properties of the high-index MBE-prepared GaAs(114)A and B surfaces were investigated in-situ by low-energy electron diffraction and surface core-level spectroscopy. Under MBE conditions both (114) surfaces show a c(2 × 2) reconstruction. We discuss three models for the c(2 × 2), which are designated as α, β1, and β2 structure analogous to the three models of the GaAs(001)-(2 × 4) reconstruction [1–3]. The surface core-level shift analysis of the A-side yields two surface components for the As 3d peak (0.64 eV and −0.55 eV) as well as for the Ga 3d peak (0.42 eV and −0.40 eV). The Ga 3d surface core-level components are only in agreement with the α model, which contains As-dimers and GaGa-bonds on (001) terraces and (111)A steps. The GaAs(1¯1¯4¯)B surface is less ordered but exhibits quite similar surface core level shifts.