Abstract
Optical, electrical, and electron-microscopy studies on granular Ag-Si and Au-Si films, prepared by cosputtering the metal and the insulator, were made over the composition range 10-90% by volume Si. Electron diffraction patterns indicate crystalline metals with lattice constants equal to those of the bulk metals. For films with less than 50-vol% Si the structure consists of amorphous Si inclusions in a continuous metal matrix; for films with more than 50-vol% Si, separate metallic particles are dispersed in an amorphous Si continuum. Near the 50-vol% Si composition the electrical resistivity increases abruptly and the infrared transmission changes from metal-like to insulatorlike behavior. The absorption and transmission peaks in the visible, observed both in the continuous-metal as well as in the continuous-insulator regimes, are explained by a generalized Maxwell-Garnett theory. It is concluded that metal particles as small as 20 Å have optical constants that do not differ significantly from those of the bulk metals.
- Received 22 March 1973
DOI:https://doi.org/10.1103/PhysRevB.8.3689
©1973 American Physical Society