Small metal (Au) particles on semiconductor (GaAs) surface

Abstract

Discontinuous metal films on semiconductor surface are very important for future application in single-electronics. Elaborated technology of chemical liquid deposition of metal from aqueous solution of gold salt allows us to obtain as well isolated nanoclusters as some nearly percolated films. Morphology and geometric parameters of metal clusters were examined by atomic force microscopy (AFM) and transmission electron microscopy (TEM).At optical investigations we used both p-polarized light reflection at several angles of incidence in visible and multi-angle of incidence (MAI) ellipsometry. Using the effective optical parameters obtained, we have calculated the dielectric function of this planar structure. Various ways for theoretical description of the dielectric response of an ensemble of metal particles on solid surface in the effective medium approximation (EMA) are considered. The most interest is exhibited to specific optical properties due to the Mie surface plasmon resonance. By AFM and TEM measurements it was found that the Au clusters were flattened in the substrate surface. The Bruggeman's approximation for oblate spheroids or truncated spheres is found as the most preferable in some range of the metal filling factor.