Using low-energy electron microscopy (LEEM), we have measured, in real time, the dewetting of single-crystal Si(001) thin films on amorphous silicon dioxide substrates, which transforms the two-dimensional (2D) thin film into three-dimensional (3D) compact Si nanocrystals. The dewetting scenario has been reported by Bussmann et al. [New J. Phys. 13, 043017 (2011)]. Analytic 2D and 3D models based on simple approximate geometries of the dewetting front have been developed to analyze LEEM measurements. They enable us to estimate the driving force for dewetting $E_s\sim 14$ eV/nm${}^2$. Starting from a Si-film thickness dependent effective dewetting activation barrier, a single Si(001) surface self-diffusion energy of $E_a=2.0\pm 0.2$ eV is derived. First nanoisland-formation dynamics measurements are discussed. Finally, grazing incidence small-angle x-ray scattering (GISAXS) is used to characterize the structure and the morphology of the Si nanocrystals created by the dewetting process.

• Received 3 November 2011

DOI:https://doi.org/10.1103/PhysRevB.84.245439