Multifractal spectra of scanning electron microscope images of SnO2 thin films prepared by pulsed laser deposition

The concept of fractal geometry has proved useful in describing structures and processes in experimental systems. In this Letter, the surface topographies of SnO2 thin films prepared by pulsed laser deposition for various substrate temperatures were measured by scanning electron microscope (SEM). Multifractal spectra f (alpha) show that the higher the substrate temperature, the wider the spectrum, and the larger the Delta f (Delta f = f (alpha(min)) - f (alpha(max))). It is apparent that the nonuniformity of the height distribution increases with the increasing substrate temperature, and the liquid droplets of SnO2 thin films are formed on previous thin films. These results show that the SEM images can be characterized by the multifractal spectra. (c) 2005 Elsevier B.V. All rights reserved.