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Phase-separated Al–Si films composed of Al nanocylinders embedded in an amorphous-Si matrix have been prepared by a sputtering method. By controlling the deposition rate, substrate temperature, and film composition, the average diameter of the Al cylinders can be varied systematically from less than 5 to 13 nm with a cylinder density ranging from 1015 to in excess of 1016 cylinders m-2. A three-dimensional simulation of phase separation in binary thin films was performed using a modified Cahn-Hilliard [J. Chem. Phys. 28, 258 (1958)] equation to understand the growth mechanism. The simulation studies indicate that the surface diffusion length and film composition are important factors which determine film morphology. Experimental and simulation studies are compared and discussed. [ABSTRACT FROM AUTHOR]

The morphology of a phase-separated binary film during spinodal decomposition, whose evolution is limited on the growth surface, is studied. The temporal evolution of the Cahn–Hilliard equation without the elastic energy term under frozen bulk approximation is solved to investigate the possibility of well-aligned nanostructures. The model simulation showed that the well-aligned phase pattern on the top surface can be formed when surface diffusion length was optimized and film thickness was larger than a certain value. These simulation results highly agree with the experimental observation of phase-separated Al–Si films. An additional simulation study indicated that well-aligned nanowires can be prepared from the initial growth stage when an initial phase pattern given on the substrate matched the periodicity of the phase pattern of deposited films. [ABSTRACT FROM AUTHOR]