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

Abstract

The current–voltage (I–V) characteristics of Au/polyaniline(PANI)/p-Si/Al structures were determined at various temperatures in the range of 90–300K. 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=0.878 eV and σ0=0.0943V 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 0.885eV and A*=55.80A/K2cm2, 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.