OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS, vol.4, no.11, pp.1779-1782, 2010 (SCI-Expanded)
Dielectric properties and ac electrical conductivity (sigma(ac)) of Al/NphAOEMA/PEDOT-PSS/ITO structure were studied in the temperature range of 120-400 K. Experimental results show that dielectric constant (epsilon'), dielectric loss(epsilon ''), dielectric loss tangent (tan delta) and sigma(ac) are strongly both temperature and bias voltage dependent. The values of epsilon' are found to increase with increasing temperature while the values of epsilon '' decrease with increasing temperature for each bias voltage. Such behaviour of dielectric properties is dependent on the amount of interfacial polarization with temperature. In addition, we obtained the values of activation energy (E-a) from the Arrhenius plots for four different bias voltages. The high E-a that is observed in the low bias voltage may be due to the sum of the energies required for the generation of the charge carriers and their motion into vacancies.