Mechanism of atomic transport on gold film fabricated by gold leaf

Abstract

The attempt to fabricate gold films on glass slide (Au/glass) and silicon wafer (Au/Si) with gold leaf was unsuccessful due to poor adhesion between the gold leaf and substrates. Alternatively, Au/glass and Au/Si films were fabricated by placing the substrate into the free space within sputtering chamber to collect the access Au vapor during the typical sputtering process for other samples. In this study, the physical changes were observed in both Au/glass and Au/Si film under the film annealing from 300⁰C-700⁰C. The visual inspection via cell phone camera, the micrograph via Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) revealed the morphological changes with respect the annealing temperature in Au films due to solid state dewetting mechanism. The changes were more pronounce in Au/glass films than Au/Si films at the same annealing temperature. The X-ray diffraction measurement three phases of Au including Au(111), Au(200), and Au(220) in Au/glass films and one phase of Au(111) in Au/silicon films. The concentration and single crystallinity of Au(111) were increased with respect to annealing temperature in Au/glass film. For Au/Si films, the concentration and single crystallinity of Au(111) were decreased at 300⁰C and then were increased at 700⁰C, respectively. The physical changes of Au films are likely due to the movement of Au atoms via solid state dewetting and recrystallization. The heat intake from annealing process is likely induced the dewetting process by increasing the kinetic energy of Au atoms. While the recrystallization process is likely occur during the cooling period of the samples. Finally, another factor that can affects the physical changes of Au films is the interface interaction between Au films and substrates.