1. A circuit structure on a substrate comprising: a reflective layer, said reflective layer being electrically conductive and having a reflectivity of between about 50% and about 90%; and a layer of chromium oxide/suboxide disposed on said reflective layer, wherein said chromium oxide/suboxide layer consists essentially of chromium and oxygen in a stoichiometric ratio between about 1:1 and about 4:1 Cr:O; wherein said chromium oxide/suboxide layer is substantially free of nitrogen.