Effects of annealing on the structure of the Au/Si(1 1 1)–H interface

The interaction between the hydrogenated silicon surface and gold, has been investigated as a function of temperature by means of high resolution core-level photoelectron spectroscopy (PES) and scanning photoelectron microscopy (SPEM). We have studied the effect of the annealing on a sample obtained by deposition of 1.5 ML of gold on an in-situ hydrogenated Si(1 1 1)-7 × 7 substrate. In order to characterize the substrate as well as the adsorbate, both Si 2p and Au 4f core-levels have been analysed. Our results show that, after annealing at 550 °C, bidimensional (2D) and tridimensional (3D) phases coexist. The two phases have been spectroscopically characterized. On the 3D phase (micrometer sized islands) a bulk-Au component is present in the Au 4f7/2 spectrum. We argue that the presence of the hydrogen layer promoted the formation of the islands. We propose a model for the temperature evolution of this interface.