An Au(1 1 1) surface was irradiated with 500 eV argon ions in a controlled manner to fabricate nano-pits. The surface morphology of nano-pits formed after 6 ML removal by ion irradiation under various temperatures was studied with STM. The depth distribution of pits at various irradiation temperatures was analyzed. There was a specific irradiation temperature at which the depth of pits became very deep in comparison with other temperatures. The results were compared with other fcc metals. The local barrier height (LBH) on surfaces with pits was measured. The LBH images were compared with the topographic images. The width where surface potential was modified near steps was found wider than the topographic width of steps. For pits lager than the critical size, the LBH value at the bottom of pits was same as that on a flat terrace except at step edges. (C) 2004 Elsevier B.V. All rights reserved.