Fractal features of titanium oxide surfaces

The fractal characteristics of TiO2 nanocrystalline films were studied and related to the efficiency of Light absorption. The fractal dimension of the film surface was computed using atomic force microscopy and D-f = 2.33 +/- 0.02 was found. Since the absorbed light energy Q(a), and therefore the re sulting photocurrent I, are proportional to the effective film area S, we c oncluded that I similar to Q(a) similar to S similar to R-Df, where R is th e linear size of the rectangular film surface. This conclusion points to a new photoelectrochemical method for the observation of the surface roughnes s and for the calculation of the fractal dimension in semiconducting films. (C) 1998 Elsevier Science B.V. All rights reserved.