Influence of the substrate on the morphological evolution of gold thin films during solid-state dewetting

The evolution of electron-beam evaporated Au thin films deposited on crystalline TiO2 (c-TiO2) and amorphous TiO2 (a-TiO2) as well as amorphous SiO2 substrates are investigated. The kinetic of dewetting is clearly dependent on the type of substrate and is faster on TiO2 substrates than on SiO2 substrates. This difference can result from the difference in adhesion energy. Furthermore, the kinetic of dewetting is faster on a-TiO2 than on c-TiO2, possibly due to the crystallization of TiO2 during annealing induced dewetting process. The morphologies of dewetted Au films deposited on crystalline TiO2 are characterized by branched holes. The XRD patterns of the Au films deposited on TiO2 substrates constituted peaks from both metallic Au and anatase TiO2. The activation energy of Au films deposited on crystalline TiO2 substrates was higher than that that of the films deposited on amorphous TiO2 substrates.