Fabrication and characterization of Schottky diodes and thin films based on poly(o-toluidine) deposited by spincoating technique

Poly(o-toluidine) (POT) thin films were fabricated by spin coating on bare glass and indium–tin–oxide (ITO)-coated glass substrates, from a solution of poly(o-toluidine) in chloroform. The optical transmittance of the as-deposited and doped films was measured in the 250–1200 nm wavelength range. These measurements showed that the optical band gaps of the undoped and doped polymer films are on the order of 3.28 and 2.7 eV, respectively, and that doping increases absorption in the near infrared region. The FT-Raman measurement on spincoated POT film is comparable to that of polyaniline. The electrochemical properties of those thin films are presented using cyclic voltammetry. ITO/POT/Al devices were fabricated by thermal evaporation of aluminum circular contacts on films deposited on ITO-coated glass. The current–voltage characteristics of the devices indicate a Schottky diode-type behavior. The current–voltage characteristics can be fitted using the modified Shockley equation. The diode parameters were calculated from I–V characteristics and discussed. On the other hand, capacitance of these structures decreased with increasing frequency.