Reactive interdiffusion and electronic barriers at metal–CdS and metal–CdSe interfaces: Control of Schottky barrier height using reactive interlayers

Abstract

Interfaces between UHV-cleaved CdS and CdSe (101̄0) surfaces and metals spanning a wide range of chemical reactivity have been investigated using UPS and XPS. We have also probed the formation of Schottky barriers via J-V and C-V analysis, thus enabling a correlation of measured electrical transport properties with observed features of chemical reaction and interdiffusion. The experimental results reveal a systematic relationship between contact barrier heights and certain critical aspects of the reacted interface region, such as the stoichiometry of semiconductor outdiffusion and the extent of Cd cation dissociation from the reacted interface region. The use of reactive Al interlayers at noble metal contacts to control these aspects of contact formation, and hence the consequent Schottky barrier height, is demonstrated.