Atomic hydrogen induced gallium nanocluster formation on the Si(1 0 0) surface

The influence of atomic hydrogen on the Si(1 0 0) substrate with submonolayer gallium surface phases – (2 × 3), (2 × 2) and (8 × 1) – as well as the deposition of gallium on monohydride terminated Si(1 0 0)–(2 × 1)-H surface were studied by synchrotron radiation photoelectron spectroscopy (SR-PES) and low energy electron diffraction (LEED) and compared with similar metal/Si systems. It was found that gallium deposition on the Si(1 0 0)–(2 × 1)-H surface at elevated temperature (400 °C) leads to a complete hydrogen desorption and formation of the same gallium surface phases as on the bare Si(1 0 0)–(2 × 1). Exposing the Si(1 0 0) substrate with (2 × 3)-Ga and (2 × 2)-Ga surface phases to atomic hydrogen results in the formation of gallium nanoclusters, surrounded by the Si(1 0 0)–(2 × 1)-H surface. These clusters have more than 2 monolayers in height and cover approximately 20–26% of surface, depending on the initial coverage. The results indicate that the cluster size and density may be controlled by initial Ga coverage and possibly by temperature.