On the barrier inhomogeneities of polyaniline/p-Si/Al structure at low temperature

The current-voltage (I-VI) characteristics of Au/polyaniline(PANI)/p-Si/Al structures were determined at various temperatures in the range of 90-300 K. The evaluation of the experimental I-V data reveals a decrease of the zero-bias barrier height (BH) and an increase of the ideality factor (n) with decreasing temperature. It was shown that the occurrence of a Gaussian distribution of then BHs is responsible for the decrease of the apparent BH, increase of the ideality factor n due to barrier height imhomogeneities that prevail at the interface. A Phi(b0) versus 1/T plot has been drawn for evidence of the Gaussian distribution of the barrier height, and Phi(b0) = 0.878 eV and sigma(0) = 0.0943 V for the mean barrier height and zero-bias standard deviation, respectively, have been obtained from this plot. Thus, a modified In(I-0/T-2) - q(2)sigma(2)(0)/2k(2) T-2 versus 1/T plot gives (Phi) over bar (b0) and A* as 0.885 eV and A* = 55.80 A/K-2 cm(2), respectively. Hence, it can be concluded that Au/PANI/p-Si/Al structure has a good rectifying contact and the temperature dependence of I-V characteristics of the rectifying contact on p-Si successfully have been explained on the basis of TE mechanism with Gaussian distribution of the barrier heights. (c) 2004 Elsevier B.V. All rights reserved.