AI/P2ClAn(CH3COOH)/p-Si/Al structure has been obtained by evaporation of the polymer P2ClAn(CH3COOH) on the front surface of p-type silicon substrate, P2ClAn: the poly(2-chloroaniline). The P2ClAn emeraldine salt was chemically synthesized by using acetic acid (CH3COOH). It has been seen that the current-voltage characteristics of the heterojunction obey to space charge-limited current model. Furthermore, P2ClAn (CH3COOH) was characterized by using Fourier Transform Infrared (FTIR) and Ultraviolet-Visible (UV-Vis) spectroscopies. An average value of mu, 2.43 x 10(-5) cm(2) V-1 s(-1), was obtained for the mobility of the P2ClAn(CH3COOH); this value is in agreement with the value of about 10(-4) cm(2) V-1 s(-1) given for the conjugated polymeric thin films in the literature. Low capacitance-voltage-frequency and conductance-frequency measurements have been made at the voltages of 0.00, 0.02 and 0.30V in the frequency range of 100 Hz-2.0 MHz. An average value of 7.91 x 10(11) cm(-2) eV(-1) for interface state density has been obtained from the frequency-capacitance characteristics. (C) 2007 Elsevier B.V. All rights reserved.