Abstract
Computer simulations have been performed for constant current mode STM images and work function measurements. Rough surfaces used for the simulations are created by making clusters on a flat surface. Simulated STM images show that R.M.S. roughness depends not only on the tip radius but also on the topography of the sample surface. The effects of setting current and work function on STM images were also studied. The results show that the dependency of STM images on the tip radius is more significant than on the setting current or work function. Simulations of work function measurements show that the work function obtained experimentally is strongly dependent on the topography of the sample surface.