Electron transport at Au/InP interface with nanoscopic exclusions

Abstract

We present an investigation of electron transport at the Au/InP metal semiconductor (MS) interface in the presence of nanoscopic barrier inhomogeneities. In particular, we focus on the transport regime wherein the low barrier inhomogeneous regions are pinched off by the depletion potential of the surrounding higher barrier region. To realize this, we have fabricated a composite MS structure comprising of a known density of nanometer sized Ag aerosol particles on InP overlayed by a uniform Au film. Temperature dependent current–voltage (I–V) measurements were performed to characterize the electron transport at the composite MS interface. The experimental observations are explained using a simple model for the MS junction current in which the Ag/InP regions are assumed to be identical and noninteracting. Our results clearly demonstrate that the electron transport at the MS interface is significantly affected by low barrier regions even in the pinch-off regime. In addition, the influence of the particle density and the Ag/InP barrier heights on the diode characteristics is also investigated. It is suggested that Schottky barrier inhomogeneities could be the main source of the usually observed larger-than-unity ideality factors in diodes. Furthermore, our results indicate possibilities of using such composites to explore the physics and applications of nanoinjecting contacts.