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

The current-voltage (I-V) 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 Φb0 versus 1/T plot has been drawn for evidence of the Gaussian distribution of the barrier height, and Φ¯b0=0.878eV and σ0 = 0.0943 V for the mean barrier height and zero-bias standard deviation, respectively, have been obtained from this plot. Thus, a modified ln(I0/T2)−q2σ02/2k2T2 versus 1/T plot gives Φ¯b0 and A* as 0.885 eV and A* = 55.80 A/K2 cm2, 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.