OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS, vol.4, no.12, pp.2132-2135, 2010 (SCI-Expanded)
The capacitance-voltage-temperature (C-V-T) and conductance-voltage-temperature (G/w-V-T) characteristics of the Al/NphAOEMA/PEDOT-PSS/ITO heterojunction structures have been investigated by taking into account the effect of the series resistance (R-s) and interface states (N-ss) in the temperature range of 120-400 K. The values of R-s and N-ss were calculated by using Nicollian and Goetzberger and Hill-Coleman methods, respectively, and both the values of R-s and N-ss decrease with increasing temperature. Experimental C-V-T and G/w-V-T characteristics confirm that the N-ss and R-s of the diode are important parameters that strongly influence the electric parameters of Al/NphAOEMA/PEDOT-PSS/ITO heterojunction structures. While the R-s are significant only in the downward curvature of the forward bias C-V characteristics and accumulation region, N-ss are significant in both the inversion and depletion region. Such behavior of R-s may be attributed to particular distribution of N-ss, restructure and reordering surface atoms with temperature and excess capacitance resulting from the N-ss in equilibrium with the semiconductor which can follow the ac signal.