Electroplating of Iridium onto Single-Crystal Silicon: Chemical and Electronic Properties of n-Si(111)/Ir Nanojunctions

Abstract

The formation of Ir nanoislands onto n-type Si(111) surfaces by electroreduction from chloride solutions containing i-propanol was investigated by electroanalytical techniques together with ex situ morphological and in-system surface spectroscopic analyses. It was found that the reduction of Ir(III) species takes place via the conduction band under semiconductor accumulation conditions. The early instants of deposition are characterized by an instantaneous type of nucleation involving the formation of Ir adatoms on surface active sites. Further growth of nuclei leads to an arrangement of finely dispersed nanoislands of size. The electronic properties of the nano n-Si(111)/Ir junctions, investigated by the impedance behavior of the conditioned surface, reveal the formation of an interfacial ultrathin oxide layer accompanying the reduction process, as confirmed by synchrotron-radiation photoelectron spectroscopy experiments.