The importance of imaging conditions in scanning tunneling microscopy for the determination of surface texture and roughness

We show that the control conditions in the feedback loop of a scanning tunn eling microscope (STM) affect the values of the surface texture parameters, including fractal characterization, when they are calculated from STM imag es of the surface. The main surface texture parameters (such as the r.m.s. roughness, kurtosis, skewness, and average wavelength) show a strong depend ence on the conditions used in the feedback loop for imaging. Fractal chara cter changes also with feedback parameters. The quality of the STM images c an be measured quantitatively by using some of the surface texture paramete rs. (C) 1999 Elsevier Science B.V. All rights reserved.