Work function measurements on cross-sectioned microcrystalline pin silicon solar cells deposited by Hot-Wire CVD are presented. The experiment is realized by combining a modified Kelvin probe experiment and a scanning force microscope. The measured surface potential revealed that the built-in electric drift field is weak in the middle of the compensated intrinsic layer. A graded donor distribution and a constant boron compensation have to be assumed within the intrinsic layer in order to obtain coincidence of the measurements and simulations. The microcrystalline p-silicon layer and the n-type transparent conducting oxide form a reverse polarized diode in series with the pin diode.