Gold films, made suitably thin, can exhibit high transparency and high conductivity at the same time. These properties are desirable, for example, when designing electrical contacts for light-emitting and light-harvesting devices. Gold deposited with conventional methods on transparent materials such as glass, however, has a strong tendency to form island films that exhibit strong optical (plasmonic) absorption and negligible electrical conductivity.
Now, using a simple surface preparation technique, researchers from the University of Iceland and Imperial College London have succeeded in suppressing this tendency to a degree where flat films down to approximately 5 nm thickness can be fabricated on glass using conventional deposition techniques. At this thickness, the theoretically expected transparency can exceed 80% in the visible range. Experiments show, however, that the actual transmission deviates from that of a perfect film, an effect that the group attributes to the presence of “fuzzy” interfaces between the gold and the neighbouring materials.