Distribution of barrier heights in Au/porous GaAs Schottky diodes from current-voltage-temperature measurements

In this work, we have studied the electrical characteristics of the Au/porous GaAs/p-GaAs diodes as a function of temperature. The (I-V)-T characteristics are analysed on the basis of thermionic emission (TE). The temperature behaviour of the barrier height potential and the ideality factor demonstrate that the current transport is controlled by the thermionic emission mechanism (TE) with Gaussian distribution of the barrier height potential. The Gaussian distribution of barrier height potential is due to barrier inhomogeneity, which is suggested to be caused by the presence of the porous GaAs interfacial layer. The experimental (I-V)-T characteristics of the Au/porous GaAs/p-GaAs heterostructure demonstrate the presence of a two Gaussian distributions having a mean barrier height potential (Phi(b0)) over bar of about 0.67 and 0.54 V and standard deviations sigma(2)(s) of about 8.4 x 10(-3) and 4.2 x 10(-3) V, respectively. Using the obtained standard deviation, the obtained Richardson constant value is in accordance with the well documented value (79.2 A cm(-2)K(-2)) of p-type GaAs and the mean barrier height (Phi(b0)) over bar is closed to the band gap of GaAs. The obtained values prove that the I-V-T characteristics of Au/porous GaAs/p-GaAs heterostructure are governed by the TE mechanism theory with two Gaussian distributions of barrier heights. (C) 2010 Elsevier B.V. All rights reserved.