Selective properties of overcoated copper granular films

Abstract

Granular copper films were formed by thermal evaporation of copper onto glass substrates maintained at 300 °C. They were subsequently overcoated at room temperature with a thick layer of aluminium having a thickness of ~100 nm. The optical properties of the overcoated films have been studied in the spectral region from 0.3 to 1.0 μm. Results indicated that the granular films preserved their aggregate structure even after overcoating. Successive annealings showed a considerable lowering of reflectivity over this spectral range and suggested the potential use of such a system of overcoated granular films for solar energy collection.