Electronic transport of Au/(Ca_1.9Pr_0.1Co₄O_x)/n-Si structures analysed over a wide temperature range

Abstract

The barrier height (BH) of the Au/(Ca_1.9Pr_0.1Co₄O_x)/n-Si structure was evaluated in the temperature range of 120–360 K using current–voltage (I–V) measurements. The zero-bias BH (Φ_Bo) 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 Φ_Bo 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 Φ_Bef. 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 (σ_o) 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.

Keywords:

• (Ca_1.9Pr_0.1Co₄O_x) interfacial layer
• current-transport mechanisms
• temperature dependent
• Gaussian distribution (GD) of BHs

Disclosure statement

No potential conflict of interest was reported by the authors.