Figure 3
Measurement of the fractal character from the AFM images. A) Representative AFM height images with N = 5122 pixels and increasing scan size S, from 0.37 to 3.33 on to 30 μm, from left to right. Height range is 180, 500 and 900 nm, respectively. Images not shown here completed the sequence, with S = 1.11, 10, and 90 μm. The white squares in the middle and right images represent the areas of previously imaged specimen regions. Two squares are traced since an image with intermediate S value had also been acquired between two consecutive shown images (S zoom factor: 3× at each step). B) Values of RMS roughness Rq reported for one whole set of AFM images with different scan size S. Error bars represent semidispersion of forward and backward scans. Empty circles are from raw AFM data, filled circles are Rq values after zero order image flattening. Lines are just guides to the eye.