Development of novel oxide multilayer mirrors at "water-window" wavelengths by atomic layer deposition / atomic layer epitaxy

Abstract

The authors proposed that novel oxide superlattice structures of crystalline TiO₂/ZnO on sapphire substrates could be fabricated for high-reflection multilayer mirrors at 2.734 nm. In the experimental study, both rutile TiO₂ (200) and wurtzite ZnO (0001) thin films were grown epitaxially on the same sapphire (0001) substrates by atomic layer epitaxy (ALE) at 450℃. the authors also demonstrated for the first time that the novel oxide superlattice structure of 10-bilayer TiO₂/ZnO on a sapphire substrate gave high reflectance at 2.734 nm.