A combination of atomic force microscopy (AFM), conductive AFM (C-AFM) and scanning Kelvin probe microscopy (SKPM) was used to investigate the correlation between the surface topography and electrical properties of GaN/InGaN light-emitting diodes (LEDs). Decreased surface potential was found at the V-defects on the p-GaN surface compared to the defect-free regions, and localized currents were detected at the edges of these V-defects under both low forward and reverse bias conditions. These findings suggest that the V-defects and the associated screw and mixed dislocations are responsible for the high leakage current observed in the LED structures. (C) 2004 Elsevier B.V. All rights reserved.