Kelvin probes force microscopy (KPFM) is one of the most powerful AFM-based methods. This technique reveals information about the topography and electrical interactions between a substrate and a probe at the same time. For electrostatic force microscopy the suitable tip should has high aspect ratio, slightly blunt and a good material to enhance the conductivity. This work has studied the use of gold nanoparticles coated silicon tips in KPFM for the first time. Comparing metal-coated standard tips with Au NP coated tips (from NEXT-TIP) can be observed that gold nanoparticles provide a sharper surface potential contrast of graphene deposited on silicon, gold sputtered on a salt surface, large and mildly rough areas of ZnO films and of DNA molecules on an insulating mica surface. This means a high lateral resolution and high sensitivity for surface charges. Furthermore, the durability and resistance of this tip is due to the certain mobility of the nanoparticles which transmits flexibility and plasticity to continuous interaction with the surface.

S. Hormeño, M. Penedo, C. Vicente and M. Luna, Nanotechnology, 24 (2013) 395701. DOI:10.1088/0957-4484/24/39/395701.