Microstructure and optical absorption of Au–MgF 2 nanoparticle cermet films

Abstract

The microstructure and optical absorption of Au–MgF2 nanoparticle cermet films with different Au contents are studied. The microstructural analysis shows that the films are mainly composed of the amorphous MgF2 matrix with embedded fcc Au nanoparticles with a mean size of 9.8–21.4nm. Spectral analysis suggests that the surface plasma resonance (SPR) absorption peak of Au particles appears at λ=492–537nm. With increasing Au content, absorption peak intensity increases, profile narrows and location redshifts. Theoretical absorption spectra are calculated based on Maxwell-Garnett theory and compared with experimental spectra.