Electronic transport of Au/(Ca1.9Pr0.1Co4Ox)/n-Si structures analysed over a wide temperature range

Abstract

The barrier height (BH) of the Au/(Ca1.9Pr0.1Co4Ox)/n-Si structure was evaluated in the temperature range of 120–360 K using current–voltage (I–V) measurements. The zero-bias BH (ΦBo) and ideality factor (n) values deduced from standard thermionic emission theory were found to be 0.35 eV and 6.30 at 120 K and 0.83 eV and 5.1 at 360 K, respectively. Because such changes in ΦBo were not in agreement with the negative temperature coefficient (α) of the Si band gap, effects of tunnelling and BH inhomogeneity were added to the analysis of junction current. With this modification, the value of ΦBef. was found to decrease with temperature at a rate of −2.4 × 10−4 eVK−1 in approximate agreement with the known α of the Si band gap. Attempts to model the inhomogeneous BH with a single Gaussian distribution were also successful, rendering a mean value of BH () of 0.997 eV and a standard deviation (σo) of 0.12 eV. Similar conclusions were drawn from additional analyses, employing the modified Richardson plots. Our results suggest that the analysis of electronic transport at this and possibly other MIS junctions should include both the effect of tunnelling and that of BH inhomogeneity.