Room-temperature growth of two-dimensional gold films on GaAs(001)

Abstract

The formation of Au overlayers on GaAs(001)-(2×4) grown by molecular-beam epitaxy has been studied at 300 K for deposited thicknesses of 0.25-15 Å. Surface geometry, composition, and electronic structure were measured by reflection electron diffraction and Auger-electron and photoelectron spectroscopy. The deposited Au was initially incorporated in a disordered continuous As-rich mixture, which showed laminar growth during the formation of the first two atomic layers. Above 4 Å, the Au overlayer grew in epitaxy with the substrate and the photoelectron spectra showed metallic characteristics. Based on these results a model is proposed for the formation of the metallic overlayer.