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Electrical characteristics of Al/polyindole Schottky barrier diodes. I. Temperature dependence



In this study, the forward and reverse bias current–voltage (IV), capacitance–voltage (CV), and conductance–voltage (G/ω–V) characteristics of Al/polyindole (Al/PIN) Schottky barrier diodes (SBDs) were studied over a wide temperature range of 140–400 K. Zero-bias barrier height ΦB0(IV), ideality factor (n), ac electrical conductivity (σac), and activation energy (Ea), determined by using thermionic emission (TE) theory, were shown fairly large temperature dispersion especially at lower temperatures due to surface states and series resistance of Al/PIN SBD. IV characteristics of the Al/PIN SBDs showed an almost rectification behavior, but the reverse bias saturation current (I0) and n were observed to be high. This high value of n has been attributed to the particular distribution of barrier heights due to barrier height inhomogeneities and interface states that present at the Al/PIN interface. The conductivity data obtained from GV measurements over a wide temperature range were fitted to the Arrhenius and Mott equations and observed linear behaviors for σac vs. 1/T and ln σac vs. 1/T1/4 graphs, respectively. The Mott parameters of T0 and K0 values were determined from the slope and intercept of the straight line as 3.8 × 107 and 1.08 × 107 Scm−1K1/2, respectively. Assuming a value of 6 × 1012 s−1 for ν0, the decay length α−1 and the density states at the Fermi energy level, N(EF) are estimated to be 8.74 Å and 1.27 × 1020 eV−1cm−3, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009