The electrical analysis of the PPy/p-Si structure has been investigated by means of I-V, C-V and C-f measurements. The diode ideality factor and the barrier height have been obtained to be n = 1.78 and Phi(b) = 0.69 eV by applying a thermionic emission theory, respectively. At high current densities in the forward direction, the series resistance effect has been observed. In general, the barrier height obtained from C-V data is greater than obtained from the I-V. This has been explained by introducing a spatial distribution of barrier heights (BHs) due to barrier height inhomogeneities that present at the PPy/p-Si interface. The C-f measurements of the structure have been performed at various biases and it has been seen that they have a good agreement between experimental and theoretical values. The interface state density N-ss and relaxation time T of the structure have been determined from the C-f characteristics. (c) 2005 Elsevier Ltd. All rights reserved.