On the intersecting behaviour of current–voltage characteristics of inhomogeneous Schottky diodes at low temperatures

Abstract

This paper explains the phenomenon of intersection of current–voltage (I–V) curves observed recently in inhomogeneous Schottky diodes at low temperatures, generated using an analytical equation. The crossing of the ln(I)–V curves appears as an abnormality when seen with respect to the conventional behaviour of ideal Schottky diodes. Here it is shown that this crossing of ln(I)–V curves is an inherent property of any Schottky diode. For a homogeneous Schottky diode, it can be observed by plotting ln(I)–V curves with zero series resistance at various temperatures. It is the presence of series resistance that keeps this intersection hidden and unobservable in homogeneous Schottky diodes. In inhomogeneous Schottky diodes with Gaussian distribution of barrier heights, this crossing is observable in the usual range of ln(I)–V curves at low temperatures even with finite (non-zero) series resistance. The analytical model of the Gaussian distribution of barrier heights thus favours crossing. However, the calculations based on the numerical integration method do not show such intersection. The detailed aspects of this intersecting behaviour of ln(I)–V curves in inhomogeneous Schottky diodes are discussed in this paper.