The conductive thin films of ferric chloride doped poly(3,4-ethylenedioxythiophene) (PEDOT: Fig. 1) were obtained by in situ vapor-pbase polymerization method under ambient conditions. Homogeneous thin conductive PEDOT films were uniformly fabricated at nano-level thickness (20-300nm) on the substrates. The surface resistance of the PEDOT films with 300nm thick was enhanced up to 500 Omega/sq, and the light transmittance were also increased as up to 95% in case of a film below 40 nm thick. The growth of highly ordered conductive PEDOT crystalline microstructure, which high anisotropy, parallel to the substrate film fabricated above 60 degreesC, was observed by atomic force microscopy (AFM). (C) 2003 Elsevier Science B.V. All rights reserved.