Object size effect on the contact potential difference measured by scanning Kelvin probe method B. Polyakov, R. Krutokhvostov, A. Kuzmin, E. Tamanis, I. Muzikante and I. Tale Eur. Phys. J. Appl. Phys., 51 2 (2010) 21201 Published online: 07 July 2010 DOI: 10.1051/epjap/2010088