Normally metallic films are required for solar energy and display related coatings. To increase the absorbing efficiency or contrast, it is necessary to apply an antireflection coating (ARC) on the metal substrate. However, the design of a metal substrate is very different from the design of a dielectric substrate, since the optical constant of metallic thin film is very dependent on its thickness and microstructure. In this study, we design and fabricate ARCs on Al substrates using SiO₂ and Nb₂O₅ as the dielectric materials and Nb for the metal films. The ARC successfully deposited on the Al substrate had the following structure: air/SiO₂/Nb₂O₅/Metal/Nb₂O₅/Al. The measured average reflectance of the ARC is less than 1% in the visible region. We found that it is better to use a highly refractive material than a low refractive material. The thickness of the metallic film can be thicker with the result that it is easier to control and has a lesser total thickness. The total thickness of the ARC is less than 200 nm. We successfully fabricated a solar absorber and OLED device with the ARC structure were successfully fabricated.

Date Published: 19 August 2010
PDF: 9 pages
Proc. SPIE 7786, Current Developments in Lens Design and Optical Engineering XI; and Advances in Thin Film Coatings VI, 77860N (19 August 2010); doi: 10.1117/12.860472

Published in SPIE Proceedings Vol. 7786:
Current Developments in Lens Design and Optical Engineering XI; and Advances in Thin Film Coatings VI
R. Barry Johnson; Virendra N. Mahajan; Simon Thibault, Editor(s)