Electrical transport at a non-ideal CrSi 2-Si junction

Abstract

Electrical transport through a CrSi 2/n-Si Schottky junction was investigated by internal photo emission spectroscopy and electrical current–voltage ( I–V) techniques in a wide temperature range. When the thermionic emission theory is used in its common form the apparent barrier height is found to be strongly temperature dependent. Internal photoemission measurements yielded a barrier height weakly temperature dependent for these samples. This difference between optical and electrical results shows that the optical transport is dominated by a single photoemission over the expected barrier at the junction while the electrical transport is determined by more than one current mechanism. Two different models based on the presence of more than one current channel and mechanism are developed in order to describe measured I–V curves. In both approaches, it was assumed that the junction's interface contains small local regions through which charge carriers can flow. In the first model, the current flow through these small regions is assumed to be of the tunneling type. Experimental results agree reasonably well by using this approach. In the second model, the barrier height in these small regions is assumed to vary statistically according to a distribution function. The result of this latter model is not satisfactory in the whole temperature range.