Charge transport mechanism under applied DC electric field in plasma polymerized diethanolamine thin films prepared by a capacitively coupled reactor

The structural and electrical characterizations of plasma polymerized (PPDEOA) thin films formed using a parallel plate capacitively coupled reactor were carried out. In Fourier transform infrared spectroscopy, it is observed that the absorption peaks appeared for different bonds in PPDEOA thin films are shifted to higher/lower wavenumbers in contrast to the corresponding peaks for the monomer, which indicate changed structure of PPDEOA. Al/PPDEOA/Al sandwiched samples were used to study the electrical properties of the thin films. The values of the power index, n, determined from the relation, J ∝ Vn are 0.53 ˂ n ˂ 1.1, that represents Ohmic behavior at the lower voltage region and in the higher voltage region, n values lie between 1.3 ˂ n ˂ 4.5 that indicate non-Ohmic behavior. In the non-Ohmic region, comparison of the theoretical values of Schottky and Poole-Frenkel coefficients with the values of experimental coefficients, the Schottky type conduction mechanism has been observed. In the low voltage region, the activation energies of PPDOA thin films are 0.06-0.14 eV and 0.23-0.69 eV in the lower and higher temperatures, respectively. The increased activation energies in the higher voltage region are 0.12 to 0.19 eV and 0.52 to 0.74 eV in the low and high temperatures, respectively.