Effects of dimension on optical transmittance of semicontinuous gold films

Abstract

The thickness dependence of dielectric response of semicontinuous gold films evaporated onto glass substrates under various temperatures has been studied. A wide range of mass thicknesses (and filling factors) was considered, up to those corresponding to continuous films. The work includes a brief introduction, description of sample preparation and transmittance measurements, as well as determination of the dielectric response function using simple phenomenological model, namely, the generalized Bruggeman approximation. The approximation considers system's dimension as a varied noninteger quantity near the percolation threshold where the correlation length is large. The results obtained show that our model is valid in the actual range and dielectric properties of films are related to their morphological peculiarities. So, we refine and supplement some of our results reported in an earlier work (Proc. SPIE 3133 (1997) 300).