Spectroscopic Characterization of Electrodeposited Poly(o-toluidine) Thin Films and Electrical Properties of ITO/Poly(o-toluidine)/Aluminum Schottky Diodes

Poly(o-toluidine) (POT) thin films were synthesized by electrochemical polymerization under cyclic voltammetric conditions from o-toluidine monomer in an aqueous solution of HCl as a supporting electrolyte. The electrosynthesized films were characterized by UV-Visible, FT-Raman, and FTIR spectroscopies. The optical transmissions of the as-deposited films were measured in the 400–900 nm wavelength range. These measurements showed that the optical band gap of the polymer films is in the order of 2.52 eV. The FT-Raman and FTIR measurements showed that the POT film is composed of imine and amine units. ITO/POT/Al devices were fabricated by thermal evaporation of aluminum circular contacts on films deposited on ITO-coated glass. The nonlinear current-voltage characteristics of these devices indicate a rectifying behavior. The diode parameters were calculated from I-V characteristics using the modified Shockley equation. The measured C-V and C-F characteristics are presented.