Surface Potential Investigation of Fullerene Derivative Film on Platinum Electrode under UV Irradiation by Kelvin Probe Force Microscopy Using a Piezoelectric Cantilever

Abstract

Dynamic-mode atomic force microscopy (DFM) combined with Kelvin probe force microscopy (KFM) has been a powerful tool not only for imaging surface topography but also for investigating surface potential on a nanometer-scale resolution. We have developed DFM/KFM using a microfabricated cantilever with a lead zirconate titanate (PZT) piezoelectric thin film used as a deflection sensor. The observed sample can be in a completely dark environment because no optics are required for cantilever deflection sensing in our experimental setup, which is also equipped with a mechanism to irradiate ultraviolet (UV) light onto the sample. We prepared a platinum-on-silicon substrate and deposited fullerene-derivative (PCBM; [6,6]-Phenyl-C₆₁-Butyric Acid Methyl Ester) film patterns by vacuum evaporation with two shadow masks in crossed directions. The energy band diagram with band-bending, it was created by simultaneously obtaining topographic and surface potential images of the same area using the developed DFM/KFM. [DOI: 10.1380/ejssnt.2015.102]